Polyacetal resin composition, composite molding using the same, and method for producing the same

Abstract

The invention is a polyacetal resin composition containing a polyacetal resin (A) and a polyethylene resin (B), in which the blending proportion of the polyacetal resin (A) occupying in the total mass of the polyacetal resin (A) and the polyethylene resin (B) is 10 to 90 mass %, the melt flow rate of the polyacetal resin (A) measured at a condition of 190 C. and 2.16 kg load is 30 g/10 minutes or less, and the polyethylene resin (B) consists of a modified polyethylene resin and the modification rate is 0.01 mass % or more based on 100 mass % of the total mass of the polyethylene resin and the melt flow rate of the polyethylene resin (B) measured at a condition of 190 C. and 2.16 kg load is 2.5 g/10 minutes or less.

Claims

1. A method of producing a composite molding having a polyacetal resin molding comprising a polyacetal resin, a polyethylene resin molding containing a polyethylene resin, and an intermediate layer provided between the polyacetal resin molding and the polyethylene resin molding, wherein the intermediate layer consists of a polyacetal resin composition consisting essentially of a polyacetal resin (A) and a polyethylene resin (B), and wherein the blending proportion of the polyacetal resin (A) occupying in the total mass of the polyacetal resin (A) and the polyethylene resin (B) is 10 to 90 mass %, a melt flow rate of the polyacetal resin (A) measured at a condition of 190 C. and 2.16 kg load is 30 g/10 minutes or less, and the polyethylene resin (B) contains a modified polyethylene resin and a modification rate is 0.01 mass % or more based on 100 mass % of the total mass of the polyethylene resin (B), and a melt flow rate of the polyethylene resin (B) measured at a condition of 190 C. and 2.16 kg load is 2.5 g/10 minutes or less, the method comprising: a first process of preparing the intermediate layer, a second process of preparing the polyacetal resin molding and a third process of preparing the polyethylene resin molding, and produces the composite molding through the first process, the second process and the third process.

2. The method of producing the composite molding according to claim 1, wherein the first process is performed before the second process and the third process, the second process is a process of preparing the polyacetal resin molding by bringing the polyacetal resin in molten state into contact with the intermediate layer to form the polyacetal resin molding on the intermediate layer, and the third process is a process of preparing the polyethylene resin molding by bringing the polyethylene resin in molten state into contact with the intermediate layer to form the polyethylene resin molding on the intermediate layer.

3. The method of producing the composite molding according to claim 2, wherein the first process, the second process and the third process are performed by a three-color molding or an insert molding.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a sectional drawing that illustrates a composite molding of the present invention.

MODE(S) FOR CARRYING OUT THE INVENTION

(2) Hereinafter, an embodiment of the composite molding of the present invention will be explained in detail with reference to FIG. 1.

(3) As illustrated in FIG. 1, the composite molding 100 has a polyacetal resin molding 10 containing a polyacetal resin, a polyethylene resin molding 20 containing a polyethylene resin, and an intermediate layer 30 that is provided between the polyacetal resin molding 10 and the polyethylene resin molding 20 and bonds the polyacetal resin molding 10 to the polyethylene resin molding 20.

(4) The intermediate layer 30 consists of a polyacetal resin composition containing a polyacetal resin (A) and a polyethylene resin (B). In this polyacetal resin composition, the blending proportion of the polyacetal resin (A) occupying in the total mass of the polyacetal resin (A) and the polyethylene resin (B) is 10 to 90 mass %, MFR thereof measured at a condition of 190 C. and 2.16 kg load is 30 g/10 minutes or less; the polyethylene resin (B) contains a modified polyethylene resin, the modification rate is 0.01 mass % or more based on 100 mass % of the total mass of the polyethylene resin (B), and MFR of the polyethylene resin (B) measured at a condition of 190 C. and 2.16 kg load is 2.5 g/10 minutes or less.

(5) The intermediate layer 30 consists of the polyacetal resin composition described above, and this polyacetal resin composition has excellent adhesive property with respect to any one of the polyacetal resin molding and the polyethylene resin molding. Therefore, according to the composite molding 100, separation between the polyacetal resin molding 10 and the polyethylene resin molding 20 can be sufficiently suppressed. Accordingly, when the composite molding 100 is used, for example, as a fuel transport part, the release of volatilized fuel through a gap generated by the separation between the polyacetal resin molding 10 and the polyethylene resin molding 20 can be sufficiently suppressed.

(6) Next, the polyacetal resin molding 10, the polyethylene resin molding 20, and the intermediate layer 30 described above will be explained in detail.

(7) (Polyacetal Resin Molding)

(8) The polyacetal resin contained in the polyacetal resin molding 10 is not particularly limited if it is a polyacetal resin having a divalent oxymethylene group, and may be a homopolymer containing a divalent oxymethylene group only as a constitutional unit, or may be a copolymer containing, for example, a divalent oxymethylene group and a divalent oxyethylene group as constitutional units.

(9) In the polyacetal resin described above, the proportion of the oxyethylene group occupying in the total mass of the oxymethylene group and the oxyethylene group is not particularly limited, and the content of oxyethylene based on 100 mole of the oxymethylene group may be, for example, 0 to 5 mol.

(10) Trioxane is ordinarily used as a main raw material to produce the polyacetal resin described above. In addition, in order to introduce the oxyethylene group into the polyacetal resin, for example, 1,3-dioxolane, ethylene oxide, or the like may be used as a comonomer.

(11) MFR of the polyacetal resin described above is not also particularly limited, and the value of MFR measured at a condition of 190 C. and 2.16 kg load may be, for example, 0.1 to 200 g/10 minutes.

(12) The polyacetal resin molding 10 may contain a polyacetal resin. Therefore, the polyacetal resin molding 10 may consist of a polyacetal resin only, or may consist of a polyacetal resin and an additive. As the additive, for example, a thermal stabilizer, an antioxidant, a weathering stabilizer, a mold-releasing agent, a lubricant, a crystal nucleating agent, an antistatic agent, an inorganic filler, a pigment, or the like may be blended.

(13) (Polyethylene Resin Molding)

(14) The polyethylene resin contained in the polyethylene resin molding 20 described above is not also particularly limited, and, for example, a high density polyethylene resin, a middle density polyethylene resin, a high pressure low density polyethylene resin, a linear low density polyethylene resin, an ultra-low density polyethylene resin, or the like may be used. The polyethylene resin molding 20 may contain a polyethylene resin. Therefore, the polyethylene resin molding 20 may consist of a polyethylene resin only, or may consist of a polyethylene resin and an additive. As the additive, for example, a thermal stabilizer, an antioxidant, a weathering stabilizer, a mold-releasing agent, a lubricant, a crystal nucleating agent, an antistatic agent, an inorganic filler, a pigment, or the like may be blended.

(15) (Intermediate Layer)

(16) (A) Polyacetal Resin

(17) The polyacetal resin (A) contained in the polyacetal resin composition constituting the intermediate layer 30 described above may be a homopolymer containing a divalent oxymethylene group only as a constitutional unit, or a copolymer containing a divalent oxymethylene group and a divalent oxyethylene group as constitutional units, but is preferably a copolymer containing a divalent oxyethylene group as a constitutional unit. When the polyacetal resin (A) is a copolymer containing a divalent oxyethylene group as a constitutional unit, it is excellent in thermal stability at the time of the melting-kneading and at the time of the injection molding.

(18) Herein, the content of the oxyethylene group based on 100 mole of the oxymethylene group in the polyacetal resin (A) described above is preferably 1.0 mole or more. In this case, it is possible for the polyacetal resin composition to have further excellent adhesive property with respect to the polyethylene resin molding in comparison to the case where the proportion of the oxyethylene group is less than 1.0 mol. The proportion of the oxyethylene group is further preferably 1.2 to 5.5 mol, and particularly preferably 1.4 to 4.0 mol.

(19) Trioxane is ordinarily used as a main raw material to produce the polyacetal resin (A) described above. In addition, in order to introduce the oxyethylene group into the polyacetal resin, for example, 1,3-dioxolane, ethylene oxide, or the like may be used as a comonomer.

(20) MFR of the polyacetal resin (A) described above measured at a condition of 190 C. and 2.16 kg load is 30 g/10 minutes or less as described above.

(21) If MFR is beyond 30 g/10 minutes, the polyacetal resin molding 10 and the intermediate layer 30 do not have excellent adhesive property to each other, and the separation of the polyacetal resin molding 10 and the intermediate layer 30 cannot be sufficiently suppressed. MFR of the polyacetal resin (A) is further preferably 20 g/10 minutes or less, and particularly preferably 10 g/10 minutes or less. However, MFR of the polyacetal resin (A) is preferably greater than 0 g/10 minutes, more preferably 1.5 g/10 minutes or more, and further preferably 2.0 g/10 minutes or more.

(22) (B) Polyethylene Resin

(23) The polyethylene resin (B) contained in the polyacetal resin composition constituting the intermediate layer 30 described above contains the modified polyethylene resin as described above. Herein, the modified polyethylene resin refers to a polyethylene resin that is graft modified with an acid or acid anhydride.

(24) The modified polyethylene resin pertaining to the present invention is produced by uniformly mixing and treating a polyethylene resin, an acid or acid anhydride and a radical generator. Examples of such a production method include, specifically, a melting-kneading method using an extruder, a Banbury mixer, a kneader, or the like; a solution method by dissolution in a suitable solvent, a slurry method by suspension in a suitable solvent, or so-called a vapor graft method, or the like. The treatment temperature is suitably selected in consideration of deterioration of the polyethylene resin, decomposition of the acid or acid anhydride, the decomposition temperature of the peroxide to be used, or the like, but ordinarily 190 to 350 C., and particularly suitably 200 to 300 C., when the production method is the melting-kneading method.

(25) A method of removing unreacted monomers (an unsaturated carboxylic acid and a derivative thereof), various by-produced components, or the like by heating, washing, or the like may be adopted in production of the modified polyethylene resin pertaining to the present invention.

(26) Examples of the radical generator used in the graft-modification include organic peroxides such as dicumyl peroxide, benzoyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, lauroyl peroxide, t-butyl peroxybenzoate, 1,1,3,3-tetramethylbutyl hydroperoxide, diisopropyl benzene hydroperoxide, t-butylcumyl peroxide, ,-bis(t-butylperoxy-m-isopropyl)benzene, di t-butyl diperoxyisophthalate, n-butyl-4,4-bis(t-butylperoxy)valerate, t-butyl peroxybenzoate, t-butyl peroxyacetate, cyclohexanone peroxide, t-butyl peroxylaurate and acetyl peroxide. Among these, preferred are those having 160 to 200 C. of the decomposition temperature for obtaining a half-life of one minute. If the decomposition temperature is too low, the decomposition reaction starts before the polyethylene resin (A) of the raw material is sufficiently plasticized in the extruder, and thus the reaction rate decreases. Reversely, if the decomposition temperature is too high, the reaction is not completed in the extruder, or the like, and the amounts of unreacted unsaturated carboxylic acids and derivatives thereof increase.

(27) Examples of the polyethylene resin that is the subject for the modification include a high density polyethylene resin, a middle density polyethylene resin, a high pressure low density polyethylene resin, a linear low density polyethylene resin, an ultra-low density polyethylene resin, or the like. One kind thereof may be used singly, or two or more kinds thereof may be used in combination.

(28) Examples of the acid modifying the polyethylene resin include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, -ethylacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid and tetrahydrophthalic acid. One kind thereof may be used singly, or two or more kinds thereof may be used in combination.

(29) Examples of the acid anhydride modifying the polyethylene resin include unsaturated carboxylic anhydrides such as maleic anhydride, citraconic anhydride, itaconic anhydride, tetrahydrophthalic anhydride, nadic anhydride and methylnadic anhydride. One kind thereof may be used singly, or two or more kinds thereof may be used in combination.

(30) Among the modified polyethylene resins described above, particularly preferred is a maleic anhydride-graft modified polyethylene resin. In this case, decomposition of the polyacetal resin can be further sufficiently suppressed and the compatibility with the polyacetal resin and the dispersibility is excellent when the polyacetal resin is melting-kneaded, in comparison to the case where the modified polyethylene resin is other than the maleic anhydride-graft modified polyethylene resin.

(31) The polyethylene resin (B) may contain one or more kinds of unmodified polyethylene resins in addition to the modified polyethylene resin. At this time, the proportion of the modified polyethylene resin in the polyethylene resin (B) is preferably 1 to 100 mass %, and further preferably 20 to 100 mass %.

(32) Examples of the unmodified polyethylene resin include a high density polyethylene resin, a middle density polyethylene resin, a high pressure low density polyethylene resin, a linear low density polyethylene resin, an ultra-low density polyethylene resin, or the like.

(33) The modification rate of the polyethylene resin (B) described above is 0.01 mass % or more with respect to the total mass of the polyethylene resin as described above. If the modification rate is less than 0.01 mass %, the polyacetal resin molding 10 and the intermediate layer 30 cannot have excellent adhesive property to each other, and the separation of the polyacetal resin molding 10 and the intermediate layer 30 cannot be sufficiently suppressed. The modification rate of the polyethylene resin (B) is preferably 0.05 to 2.0 mass %, and further preferably 0.10 to 1.0 mass %. Herein, the modification rate of the polyethylene resin (B) described above is defined as follow. In other words, the modification rate of the polyethylene resin (B) is defined as the proportion (percent) by mass parts of the acid or acid anhydride grafted to the polyethylene molecule with respect to 100 mass parts of the polyethylene resin.

(34) The density of the polyethylene resin (B) described above is preferably 0.954 g/cm.sup.3 or less. In this case, it is possible for the polyacetal resin composition to have further excellent adhesive property with respect to the polyacetal resin molding 10 in comparison to the case where the density is beyond 0.954 g/cm.sup.3. The density of the polyethylene resin (B) described above is further preferably 0.912 to 0.945 g/cm.sup.3. Herein, the density of the polyethylene resin (B) described above is measured by the method in accordance with JIS K7112.

(35) MFR of the polyethylene resin (B) described above measured at a condition of 190 C. and 2.16 kg load is 2.5 g/10 minutes or less as described above. Herein, the MFR of the polyethylene resin (B) described above is measured by the method in accordance with ASTM-D1238 standards.

(36) If MFR is beyond 2.5 g/10 minutes, the polyacetal resin molding 10 and the intermediate layer 30 cannot have excellent adhesive property to each other, and the separation of the polyacetal resin molding 10 and the intermediate layer 30 cannot be sufficiently suppressed. MFR of the polyethylene resin (B) is preferably 0.01 to 2.0 g/10 minutes, and particularly preferably 0.01 to 1.8 g/10 minutes.

(37) In the intermediate layer 30 described above, the blending proportion of the polyacetal resin (A) occupying in the total mass of the polyacetal resin (A) and the polyethylene resin (B) is 10 to 90 mass % as described above.

(38) If the blending proportion of the polyacetal resin (A) is less than 10 mass %, the polyacetal resin molding 10 and the intermediate layer 30 cannot have excellent adhesive property to each other, and the separation of the polyacetal resin molding 10 and the intermediate layer 30 cannot be sufficiently suppressed. On the other hand, if the blending proportion of the polyacetal resin (A) is beyond 90 mass %, the polyethylene resin molding 20 and the intermediate layer 30 cannot have excellent adhesive property to each other, and the separation of the polyethylene resin molding 20 and the intermediate layer 30 cannot be sufficiently suppressed. The blending proportion of the polyacetal resin (A) occupying in the total mass of the polyacetal resin (A) and the polyethylene resin (B) is preferably 10 to 80 mass %, and further preferably 20 to 70 mass %.

(39) (C) Other Components

(40) A modifier may be further contained in the polyacetal resin composition constituting the intermediate layer 30. Herein, examples of the modifier include isocyanates, or the like. Examples of the isocyanate specifically include monovalent isocyanate compounds such as methyl isocyanate, ethyl isocyanate, propyl isocyanate, butyl isocyanate, hexyl isocyanate, octyl isocyanate, decyl isocyanate, dodecyl isocyanate, hexadecyl isocyanate, octadecyl isocyanate, eicosyl isocyanate, methacrylate ethyl 2-isocyanate and phenyl isocyanate; divalent isocyanate compounds such as methylene diisocyanate, ethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, hexadecamethylene diisocyanate, eicosamethylene diisocyanate, methylene bis(4,1-cyclohexanediyl)diisocyanate or a carbodiimide-modified body thereof, 4,4-diphenyl methanediisocyanate or a carbodiimide-modified body thereof, 1,5-naphthalene diyldiisocyanate and 3,3-dimethylbiphenyl-4,4-diyl diisocyanate, or the like. The modifier is blended preferably in 0.05 to 5.0 mass parts, more preferably in 0.1 to 1.0 mass parts with respect to 100 mass parts of the sum of the polyacetal resin and the polyethylene resin. In this case, an advantage of improvement in the toughness and the adhesive property of the intermediate layer 30 is obtained.

(41) Next, a method of producing the composite molding 100 will be explained in detail.

(42) The method of producing the composite 100 includes a first process of preparing the intermediate layer 30, a second process of preparing the polyacetal resin molding 10 and a third process of preparing the polyethylene resin molding 20, and produces the composite molding 100 through the first process, the second process and the third process. Herein, the sequence of the first process, the second process and the third process does not matter. In other words, the first process, the second process and the third process may be performed sequentially, or the second process, the first process and the third process may be performed sequentially, or the third process, the first process and the second process may be performed sequentially. In addition, the first process, the second process and the third process may be also performed at the same time.

(43) Specifically, the composite molding 100 is produced by a method in which the polyacetal resin molding 10, the intermediate layer 30 and the polyethylene resin molding 20 are molded, respectively, and then they are welded to each other; a method in which the polyacetal resin molding 10 and the intermediate layer 30 are two-color molded to form a two-color molding, and then the two-color molding is welded with the polyethylene resin molding 20; a method in which the polyethylene resin molding 20 and the intermediate layer 30 are two-color molded to form a two-color molding, and then the two-color molding is welded with the polyacetal resin molding 10; a method in which the polyacetal resin molding 10, the intermediate layer 30 and the polyethylene resin molding 20 are three-color molded; a method in which the intermediate layer 30 is prepared and then the polyacetal resin molding 10 and the polyethylene resin molding 20 are formed on both sides of the intermediate layer 30, respectively, or the like. Among these, particularly preferred is a method in which the polyacetal resin molding 10, the intermediate layer 30 and the polyethylene resin molding 20 are three-color molded to form the composite molding 100 from the viewpoint of the productivity.

(44) Herein, the method in which the polyacetal resin molding 10, the intermediate layer 30 and the polyethylene resin molding 20 are three-color molded to produce the composite molding 100 will be explained.

(45) First, three common dies having an identical shape are placed on a rotating plate. On the other hand, a primary die, a secondary die and a tertiary die having different shapes from each other are prepared. The primary die is used for producing the polyacetal resin molding 10 together with the common die, and the secondary die is used for producing the intermediate layer 30 together with the common die and the polyacetal resin molding 10. The tertiary die is used for producing the polyethylene resin molding 20 together with the common die, the polyacetal resin molding 10 and the intermediate layer 30.

(46) First of all, the polyacetal resin molding 10 is produced with one of the common dies and the primary die (the second process). Next, the rotating plate is rotated, and the polyacetal resin composition for forming the intermediate layer is supplied while being heated into the space formed by the polyacetal resin molding 10, the common die, and the secondary die, and then cooled.

(47) In this way, the intermediate layer 30 is formed on the polyacetal resin molding 10, and the structure is obtained (the first process).

(48) Next, the rotating plate is rotated, and the raw materials for forming the polyethylene resin molding 20 is supplied while being heated into the space formed by the structure, the common die and the tertiary die, and then cooled.

(49) In this way, the polyethylene resin molding 20 is formed on the intermediate layer 30 of the structure (the third process), and the composite molding 100 is obtained.

(50) Meanwhile, in the production methods above, the sequence of the second process and the third process may be changed.

(51) In addition, among the production methods described above, preferred is a method in which the intermediate layer 30 is prepared, and then the polyacetal resin molding 10 and the polyethylene resin molding 20 are formed on both sides of the intermediate layer 30, respectively from the viewpoint of suppressing the separation between the layers in the composite molding 100.

(52) Herein, this production method will be explained in detail.

(53) In this production method, first, the intermediate layer 30 is prepared (the first process).

(54) Next, the polyacetal resin in molten state is brought into contact with the intermediate layer 30 to form the polyacetal resin molding 10 on the intermediate layer 30 whereby to prepare the polyacetal resin molding 10 (the second process).

(55) Next, the polyethylene resin in molten state is brought into contact with the intermediate layer 30, to form the polyethylene resin molding 20 on the intermediate layer 30 whereby to prepare the polyethylene resin molding 20 (the third process).

(56) In this way, the composite molding 100 is obtained.

(57) According to this production method, in the obtained composite molding 100, it is possible to further improve the adhesion strength between the intermediate layer 30 and the polyacetal resin molding 10, and the adhesion strength between the intermediate layer 30 and the polyethylene resin molding 20 in comparison to the case where the first process is not performed before the second process and the third process.

(58) In the production method above, the sequence of the second process and the third process may be changed, and the second process and the third process may be performed at the same time.

(59) The first process, the second process and the third process described above may be performed specifically by the three-color molding or the insert molding.

(60) The composite molding of the present invention may be applied, for example, to a valve device, a re-circulation line, a vent line, a flange for a fuel sender module, and a connecting part for a fuel tank such as a swirl baffle plate oil sump bonded to the internal wall surface of a fuel tank, or the like.

(61) In addition, although the polyacetal resin composition of the present invention constitutes the intermediate layer 30 of the composite molding 100 in the embodiment described above, the polyacetal resin composition of the present invention may be applied not only as a material constituting the intermediate layer 30 of the composite molding 100 but also be applied as an adhesive for connecting the polyacetal resin molding 10 containing a polyacetal resin to the polyethylene resin molding 20 containing a polyethylene resin.

EXAMPLES

(62) Hereinafter, the present invention will be specifically explained with Examples and Comparative examples, but the present invention is not limited to Examples below.

(63) The materials used in Examples and Comparative examples are as follows.

(64) (A) Polyacetal Resin

(65) (A-1) Polyacetal Resin-1

(66) Acetal copolymer having an oxyethylene group content of 3.4 mole based on 100 mole of the oxymethylene group, and MFR (ASTM-D1238 standards: 190 C. and 2.16 kg) of 10 g/10 minutes

(67) (A-2) Polyacetal Resin-2

(68) Acetal copolymer having an oxyethylene group content of 1.4 mole based on 100 mole of the oxymethylene group, and MFR (ASTM-D1238 standards: 190 C. and 2.16 kg) of 9.0 g/10 minutes

(69) (A-3) Polyacetal Resin-3

(70) Acetal copolymer having an oxyethylene group content of 1.4 mole based on 100 mole of the oxymethylene group, and MFR (ASTM-D1238 standards: 190 C. and 2.16 kg) of 52 g/10 minutes

(71) (A-4) Polyacetal Resin-4

(72) Acetal copolymer having an oxyethylene group content of 1.4 mole based on 100 mole of the oxymethylene group, and MFR (ASTM-D1238 standards: 190 C. and 2.16 kg) of 2.5 g/10 minutes

(73) (A-5) Polyacetal Resin-5

(74) Acetal copolymer having a oxyethylene group content of 3.4 mole based on 100 mole of the oxymethylene group, and MFR (ASTM-D1238 standards: 190 C. and 2.16 kg) of 27 g/10 minutes

(75) Mole number of oxyethylene group per 100 mole of oxymethylene group in polymer: 10 g of the copolymer is put into 100 ml of 3NHCl aqueous solution, and heated and decomposed at 120 C. for 2 hours in an airtight container. The aqueous solution is cooled, and then measured with gas chromatography (FID), and the content of the oxyethylene group is represented by the mole number with respect to 100 mole of the oxymethylene group of the polymer.

(76) (B) Polyethylene Resin

(77) (B-1) Polyethylene Resin-1

(78) Maleic anhydride-modified polyethylene resin having a density of 0.922 g/cm.sup.3 (in accordance with JIS K7112), MFR (ASTM-D1238 standards: 190 C. and 2.16 kg) of 0.35 g/10 minutes, and a maleic anhydride modification rate of 0.28 mass %

(79) (B-2) Polyethylene Resin-2

(80) Maleic anhydride-modified polyethylene resin having a density of 0.922 g/cm.sup.3 (in accordance with JIS K7112), MFR (ASTM-D1238 standards: 190 C. and 2.16 kg) of 0.24 g/10 minutes, and a maleic anhydride modification rate of 0.64 mass %

(81) (B-3) Polyethylene Resin-3

(82) Maleic anhydride-modified polyethylene resin having a density of 0.954 g/cm.sup.3 (in accordance with JIS K7112), MFR (ASTM17-D1238 standards: 190 C. and 2.16 kg) of 0.26 g/10 minutes, and a maleic anhydride modification rate of 0.29 mass %

(83) (B-4) Polyethylene Resin-4

(84) Maleic anhydride-modified polyethylene resin having a density of 0.954 g/cm.sup.3 (in accordance with JIS K7112), MFR (ASTM-D1238 standards: 190 C. and 2.16 kg) of 0.17 g/10 minutes, and a maleic anhydride modification rate of 0.54 mass %

(85) (B-5) Polyethylene Resin-5

(86) Maleic anhydride-modified polyethylene resin having a density of 0.925 g/cm.sup.3 (in accordance with JIS K7112), MFR (ASTM-D1238 standards: 190 C. and 2.16 kg) of 11.6 g/10 minutes, and a maleic anhydride modification rate of 0.20 mass %

(87) (B-6) Polyethylene Resin-6

(88) Maleic anhydride-modified polyethylene resin having a density of 0.925 g/cm.sup.3 (in accordance with JIS K7112), MFR (ASTM-D1238 standards: 190 C. and 2.16 kg) of 9.7 g/10 minutes, and a maleic anhydride modification rate of 0.42 mass %

(89) (B-7) Polyethylene Resin-7

(90) Maleic anhydride-modified polyethylene resin having a density of 0.956 g/cm.sup.3 (in accordance with JIS K7112), MFR (ASTM-D1238 standards: 190 C. and 2.16 kg) of 15.9 g/10 minutes, and a maleic anhydride modification rate of 0.21 mass %

(91) (B-8) Polyethylene Resin-8

(92) Maleic anhydride-modified polyethylene resin having a density of 0.956 g/cm.sup.3 (in accordance with JIS K7112), MFR (ASTM-D1238 standards: 190 C. and 2.16 kg) of 12.1 g/10 minutes, and a maleic anhydride modification rate of 0.40 mass %

(93) (B-9) Polyethylene Resin-9

(94) Polyethylene resin having a density of 0.922 g/cm.sup.3 (in accordance with JIS K7112), MFR (ASTM-D1238 standards: 190 C. and 2.16 kg) of 1.0 g/10 minutes, and a maleic anhydride modification rate of 0 mass %

(95) (B-10) Polyethylene Resin-10

(96) Maleic anhydride-modified polyethylene resin having a density of 0.922 g/cm.sup.3 (in accordance with JIS K7112), MFR (ASTM-D1238 standards: 190 C. and 2.16 kg) of 0.9 g/10 minutes, and a maleic anhydride modification rate of 0.28 mass %

(97) (B-11) Polyethylene Resin-11

(98) Maleic anhydride-modified polyethylene resin having a density of 0.922 g/cm.sup.3 (in accordance with JIS K7112), MFR (ASTM-D1238 standards: 190 C. and 2.16 kg) of 1.8 g/10 minutes, and a maleic anhydride modification rate of 0.28 mass %

(99) (B-12) Polyethylene Resin-12

(100) Maleic anhydride-modified polyethylene resin having a density of 0.922 g/cm.sup.3 (in accordance with JIS K7112), MFR (ASTM-D1238 standards: 190 C. and 2.16 kg) of 2.8 g/10 minutes, and a maleic anhydride modification rate of 0.28 mass %

(101) (B-13) Polyethylene Resin-13

(102) Polyethylene resin having a density of 0.933 g/cm.sup.3 (in accordance with JIS K7112), MFR (ASTM-D1238 standards: 190 C. and 2.16 kg) of 0.50 g/10 minutes, and a maleic anhydride modification rate of 0.11 mass %, and consisting of 40 mass % of maleic anhydride-modified polyethylene resin having a density of 0.954 g/cm.sup.3 (in accordance with JIS K7112), MFR (ASTM-D1238 standards: 190 C. and 2.16 kg) of 0.26 g/10 minutes, and a maleic anhydride modification rate of 0.29 mass %; 35 mass % of unmodified linear low density polyethylene resin having a density of 0.928 g/cm.sup.3 (in accordance with JIS K7112) and MFR (ASTM-D1238 standards: 190 C. and 2.16 kg) of 0.90 g/10 minutes; and 25 mass % of unmodified linear low density polyethylene resin having a density of 0.908 g/cm.sup.3 (in accordance with JIS K7112) and MFR (ASTM-D1238 standards: 190 C. and 2.16 kg) of 1.0 g/10 minutes

(103) (B-14) Polyethylene Resin-14

(104) Polyethylene resin having a density of 0.933 g/cm.sup.3 (in accordance with JIS K7112), MFR (ASTM-D1238 standards: 190 C. and 2.16 kg) of 0.50 g/10 minutes, and a maleic anhydride modification rate of 0.21 mass %, and consisting of 40 mass % of maleic anhydride-modified polyethylene resin having a density of 0.954 g/cm.sup.3 (in accordance with JIS K7112), MFR (ASTM-D1238 standards: 190 C. and 2.16 kg) of 0.17 g/10 minutes, and a maleic anhydride modification rate of 0.54 mass %; 35 mass % of unmodified linear low density polyethylene resin having a density of 0.928 g/cm.sup.3 (in accordance with JIS K7112) and MFR (ASTM-D1238 standards: 190 C. and 2.16 kg) of 0.90 g/10 minutes; and 25 mass % of unmodified linear low density polyethylene resin having a density of 0.908 g/cm.sup.3 (in accordance with JIS K7112) and MFR (ASTM-D1238 standards: 190 C. and 2.16 kg) of 1.0 g/10 minutes

Examples 1 to 15 and Comparative Examples 1 to 11

(105) The polyacetal resin (A) and the polyethylene resin (B) indicated in Tables 1 to 4 were mixed at the blending amounts indicated in Tables 1 to 4 with SUPER MIXER manufactured by KAWATA MFG.CO., LTD. to give a mixture, and then this mixture was melting-kneaded with a biaxial extruder (PCM-30 manufactured by Ikegai Co., Ltd., screw diameter: 30 mm) to perform extrusion, and the strand discharged from the extruder was cooled in a water tank and was cut with a pelletizer to give pellets of the polyacetal resin compositions of Examples 1 to 15 and Comparative examples 1 to 11. Meanwhile, the unit of the blending amount in Tables 1 to 4 is mass %.

(106) <Evaluation for Adhesive Property>

(107) (1) Test 1 for Adhesive Property with Respect to Polyacetal Resin Molding (POM Molding)

(108) The pellets of the polyacetal resin compositions of Examples 1 to 15 and Comparative examples 1 to 11 were injection-molded at a condition of a resin temperature of 240 C. and a die temperature of 40 C. using an injection molding machine (PS-40 manufactured by NISSEI PLASTIC INDUSTRIAL CO., LTD), to give a test film of 123 mm13 mm0.8 mm (thickness). A half side (62 mm length) of one surface among both surfaces having the greatest area of the obtained test film was protected with a heat-resistant seal consisting of polyimide having a thickness of 0.03 mm (herein, the surface protected with the heat-resistant seal of the one surface is referred to as the protected surface 1, and the surface not protected with the heat-resistant seal is referred to as the non-protected surface 1). Then, the test film was inserted into the die cavity of 123 min13 mm4.0 mm (thickness), and a polyacetal resin (an acetal copolymer having a proportion of the oxyethylene group occupying in the total mass of the oxymethylene group and the oxyethylene group of 1.7 mol, and MFR (ASTM-D1238 standards: 190 C. and 2.16 kg) of 9 g/10 minutes) was introduced to the cavity at a condition of a resin temperature of 230 C. and a die temperature of 120 C., and a polyacetal resin molding was formed on the non-protected surface 1 and the heat-resistant seal of the test film, to give a laminate A.

(109) From the thus-obtained laminate A, the heat-resistant seal was peeled off together with a portion of the polyacetal resin molding formed on the heat-resistant seal. Then, the remaining portion of the polyacetal resin molding formed on the non-protected surface 1 of the test film was fixed at the lower fixture (fixed side) of the tension tester (manufactured by Instron, product name: 5544), and the test film was fixed at the upper fixture (movable side). Then, the upper fixture was displaced upward, that is, in the vertical direction with respect to the interface of the remaining portion of the polyacetal resin molding and the test film at a speed of 200 mm/min, whereby to separate the test film from the polyacetal resin molding. In other words, 90 peel test between the test film and the polyacetal resin molding was performed. At this time, the maximum tension strength detected with the load cell of the tension tester was defined as the adhesion strength of the test film with respect to the polyacetal resin molding. The results are shown in Tables 1 to 4.

(110) (2) Test 2 for Adhesive Property with Respect to Polyacetal Resin Molding (POM Molding)

(111) A polyacetal resin (an acetal copolymer having a proportion of the oxyethylene group occupying in the total mass of the oxymethylene group and the oxyethylene group of 1.7 mol, and MFR (ASTM-D1238 standards: 190 C. and 2.16 kg) of 9 g/10 minutes) was injection-molded at a condition of a resin temperature of 230 C. and a die temperature of 120 C. using an injection molding machine (PS-40 manufactured by Nissei Resin Industry Co.), to give a polyacetal resin molding of 123 mm13 mm3.2 mm (thickness). The half side (62 mm length) of one surface among both surfaces having the greatest area of the obtained polyacetal resin molding was protected with a heat-resistant seal consisting of polyimide having a thickness of 0.03 mm (herein, the surface protected with the heat-resistant seal of the one surface is referred to as the protected surface 2, and the surface not protected with the heat-resistant seal is referred to as the non-protected surface 2). Then, the polyacetal resin molding was inserted into the die cavity of 123 mm13 mm4.0 mm (thickness), and the pellets of the polyacetal resin compositions of Examples 1 to 15 and Comparative examples 1 to 11 were introduced to the cavity at a condition of a resin temperature of 230 C. and a die temperature of 120 C., and the test film was formed on the non-protected surface 2 and the heat-resistant seal of the polyacetal resin molding, to give a laminate B.

(112) From the laminate B described above, the heat-resistant seal was peeled off together with a portion of the test film formed thereon. Then, the remaining portion of the test film formed on the non-protected surface 2 of the polyacetal resin molding was fixed at the lower fixture (fixed side) of the tension tester (manufactured by Instron, product name: 5544), and a polyacetal resin molding was fixed at the upper fixture (movable side). Then, the upper fixture was displaced upward, that is, in the vertical direction with respect to the interface of the remaining portion of the test film and the polyacetal resin molding at a speed of 200 mm/min, whereby to separate the polyacetal resin molding from the test film. In other words, 90 peel test between the test film and the polyacetal resin molding was performed. At this time, the maximum tension strength detected with the load cell of the tension tester was defined as the adhesion strength of the test film with respect to the polyacetal resin molding. The results are shown in Tables 1 to 4.

(113) (3) Test 3 for Adhesive Property with Respect to Polyethylene Resin Molding (PE Molding)

(114) The pellets of the polyacetal resin compositions of Examples 1 to 15 and Comparative examples 1 to 11 were injection-molded at a condition of a resin temperature of 240 C. and a die temperature of 40 C. using an injection molding machine (PS-40 manufactured by NISSEI PLASTIC INDUSTRIAL CO., LTD), to give a test film of 123 mm13 mm0.8 mm (thickness). The half side (62 mm length) of one surface among both surfaces having the greatest area of the obtained test film was protected with a heat-resistant seal consisting of polyimide having a thickness of 0.03 mm (herein, the surface protected with the heat-resistant seal of the one surface is referred to as the protected surface 3, and the surface not protected with the heat-resistant seal is referred to as the non-protected surface 3). Then, the test film was inserted into the die cavity of 123 mm13 mm4.0 mm (thickness), and a polyethylene resin (manufactured by Japan Polyethylene Corporation, product name: NOVATEC HD HJ221, having a density of 0.949 g/cm.sup.3 (in accordance with JIS K7112), and MFR (ASTM-D1238 standards: 190 C. and 21.6 kg) of 13 g/10 minutes) was introduced to the cavity at a condition of a resin temperature of 230 C. and a die temperature of 120 C., and the polyethylene resin molding was formed on the non-protected surface 3 and the heat-resistant seal of the test film, to give a laminate C.

(115) From the thus-obtained laminate C, the heat-resistant seal was peeled off together with a portion of the polyethylene resin molding formed thereon. Then, the remaining portion of the polyethylene resin molding formed on the non-protected surface 3 of the test film was fixed at the lower fixture (fixed side) of the tension tester (manufactured by Instron, product name: 5544), and the test film was fixed at the upper fixture (movable side). Then, the upper fixture was displaced upward, that is, in the vertical direction with respect to the interface of the remaining portion of the polyethylene resin molding and the test film at a speed of 200 mm/min, whereby to separate the test film from the polyethylene resin molding. In other words, 90 peel test between the test film and the polyethylene resin molding was performed. At this time, the maximum tension strength detected with the load cell of the tension tester was defined as the adhesion strength of the test film with respect to the polyethylene resin molding. The results are shown in Tables 1 to 4.

(116) (4) Test 4 for Adhesive Property with Respect to Polyethylene Resin Molding (PE Molding)

(117) A polyethylene resin (manufactured by Japan Polyethylene Corporation, product name: NOVATEC HD HJ221, having a density of 0.949 g/cm.sup.3 (in accordance with JIS K7112), and MFR (ASTM-D1238 standards: 190 C. and 21.6 kg) of 13 g/10 minutes) was injection-molded at a condition of a resin temperature of 240 C. and a die temperature of 40 C. using an injection molding machine (PS-40 manufactured by NISSEI PLASTIC INDUSTRIAL CO., LTD), to give a polyethylene resin molding of 123 mm13 mm3.2 mm (thickness). The half side (62 mm length) of one surface among both surfaces having the greatest area of the obtained polyethylene resin molding was protected with a heat-resistant seal consisting of polyimide having a thickness of 0.03 mm (herein, the surface protected with the heat-resistant seal of the one surface described above is referred to as the protected surface 4, and the surface not protected with the heat-resistant seal is referred to as the non-protected surface 4). Then, the polyethylene resin molding was inserted into the die cavity of 123 mm13 mm4.0 mm (thickness), and the pellets of the polyacetal resin compositions of Examples 1 to 15 and Comparative examples 1 to 11 were introduced to the cavity at a condition of a resin temperature of 230 C. and a die temperature of 120 C., and the test film was formed on the non-protected surface 4 and the heat-resistant seal of the polyethylene resin molding, to give a laminate D.

(118) From the laminate D described above, the heat-resistant seal was peeled off together with a portion of the test film formed thereon. Then, the remaining portion of the test film formed on the non-protected surface 4 of the polyethylene resin molding was fixed at the lower fixture (fixed side) of the tension tester (manufactured by Instron, product name: 5544), and the polyethylene resin molding was fixed at the upper fixture (movable side). Then, the upper fixture was displaced upward, that is, in the vertical direction with respect to the interface of the remaining portion of the test film and the polyethylene resin molding at a speed of 200 mm/min, whereby to separate the polyethylene resin molding from the test film. In other words, 90 peel test between the test film and the polyethylene resin molding was performed. At this time, the maximum tension strength detected with the load cell of the tension tester was defined as the adhesion strength of the test film with respect to the polyethylene resin molding. The results are shown in Tables 1 to 4.

(119) The passing criteria with respect to the adhesive property was as follows.

(120) Passing criteria: The adhesion strength is 25N or more in any one of the tests 1 to 4 for adhesive property

(121) TABLE-US-00001 TABLE 1 Example Example Example Example Example Example Example Example 1 2 3 4 5 6 7 8 Composition (A) Polyacetal resin A-1 30 30 30 30 A-2 30 45 60 A-3 A-4 30 A-5 (B) Polyethylene resin B-1 70 70 70 55 40 B-2 70 B-3 70 B-4 70 B-5 B-6 B-7 B-8 B-9 B-10 B-11 B-12 B-13 B-14 MFR of (A) Polyacetal resin (g/10 minutes) 10 10 10 10 2.5 9 9 9 Content of Oxyethylene group of (A) 3.4 3.4 3.4 3.4 1.4 3.4 3.4 3.4 Polyacetal resin (Mole number per 100 mole of Oxymethylene group) MFR of (B) Polyethylene resin (g/10 minutes) 0.35 0.24 0.26 0.17 0.35 0.35 0.35 0.35 Modification rate of (B) Polyethylene 0.28 0.64 0.29 0.54 0.28 0.28 0.28 0.28 resin (mass %) Density of (B) Polyethylene resin (g/cm.sup.3) 0.922 0.922 0.954 0.954 0.922 0.922 0.922 0.922 Test 1 for adhesive Adhesion strength to 37 29 28 26 46 35 38 40 property (Test film to POM molding (N) POM molding) Test 2 for adhesive Adhesion strength to 35 27 26 25 40 31 34 37 property (POM molding POM molding (N) to Test film) Test 3 for adhesive Adhesion strength to 65 61 43 50 52 51 42 37 property (Test film to PE molding (N) PE molding) Test 4 for adhesive Adhesion strength to 53 50 35 41 43 42 32 26 property (PE molding PE molding (N) to Test film)

(122) TABLE-US-00002 TABLE 2 Example Example Example Example Example Example Example 9 10 11 12 13 14 15 Composition (A) Polyacetal resin A-1 30 30 30 A-2 30 30 35 A-3 A-4 A-5 30 (B) Polyethylene resin B-1 70 B-2 B-3 B-4 B-5 B-6 B-7 B-8 B-9 B-10 70 B-11 70 B-12 B-13 70 B-14 70 70 65 MFR of (A) Polyacetal resin (g/10 minutes) 27 10 10 9 10 9 9 Content of Oxyethylene group of (A) Polyacetal resin 3.4 3.4 3.4 3.4 3.4 3.4 3.4 (Mole number per 100 mole of Oxymethylene group) MFR of (B) Polyethylene resin (g/10 minutes) 0.35 0.90 1.8 0.5 0.5 0.5 0.5 Modification rate of (B) Polyethylene resin (mass %) 0.28 0.28 0.28 0.11 0.21 0.21 0.21 Density of (B) Polyethylene resin (g/cm.sup.3) 0.922 0.922 0.922 0.933 0.933 0.933 0.933 Test 1 for adhesive property Adhesion strength to POM 26 33 27 35 33 37 39 (Test film to POM molding) molding (N) Test 2 for adhesive property Adhesion strength to POM 25 30 25 32 30 35 36 (POM molding to Test film) molding (N) Test 3 for adhesive property Adhesion strength to PE 64 59 57 57 59 61 55 (Test film to PE molding) molding (N) Test 4 for adhesive property Adhesion strength to PE 53 49 48 48 49 50 45 (PE molding to Test film) molding (N)

(123) TABLE-US-00003 TABLE 3 Comparative Comparative Comparative Comparative Comparative Comparative Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Composition (A) Polyacetal resin A-1 30 30 30 30 55 30 A-2 A-3 A-4 A-5 (B) Polyethylene resin B-1 B-2 B-3 B-4 B-5 70 B-6 70 B-7 70 B-8 70 45 B-9 70 B-10 B-11 B-12 MFR of (A) Polyacetal resin (g/10 minutes) 10 10 10 10 10 10 Content of Oxyethylene group of (A) Polyacetal resin 3.4 3.4 3.4 3.4 3.4 3.4 (Mole number per 100 mole of Oxymethylene group) MFR of (B) Polyethylene resin (g/10 minutes) 11.6 9.7 15.9 12.1 12.1 1.0 Modification rate of (B) Polyethylene resin (mass %) 0.20 0.42 0.21 0.40 0.40 0.00 Density of (B) Polyethylene resin (g/cm.sup.3) 0.925 0.925 0.956 0.956 0.956 0.922 Test 1 for adhesive property Adhesion strength to POM 16 15 0 0 14 11 (Test film to POM molding) molding (N) Test 2 for adhesive property Adhesion strength to POM 9 9 0 0 7 5 (POM molding to Test film) molding (N) Test 3 for adhesive property Adhesion strength to PE 53 55 129 123 45 68 (Test film to PE molding) molding (N) Test 4 for adhesive property Adhesion strength to PE 43 43 118 113 31 59 (PE molding to Test film) molding (N)

(124) TABLE-US-00004 TABLE 4 Comparative Comparative Comparative Comparative Comparative Example 7 Example 8 Example 9 Example 10 Example 11 Composition (A) Polyacetal resin A-1 100 4 30 A-2 A-3 30 A-4 A-5 (B) Polyethylene resin B-1 100 70 96 B-2 B-3 B-4 Bo B-6 B-7 B-8 B-9 B-10 B-11 B-12 70 MFR of (A) Polyacetal resin (g/10 minutes) 10 52 10 10 Content of Oxyethylene group of (A) Polyacetal resin 3.4 1.4 3.4 3.4 (Mole number per 100 mole of Oxymethylene group) MFR of (B) Polyethylene resin (g/10 minutes) 0.35 0.35 0.35 2.8 Modification rate of (B) Polyethylene resin (mass %) 0.28 0.28 0.28 0.28 Density of (B) Polyethylene resin (g/cm.sup.3) 0.922 0.922 0.922 0.922 Test 1 for adhesive property Adhesion strength to POM 620 0 17 5 17 (Test film to POM molding) molding (N) Test 2 for adhesive property Adhesion strength to POM 620 0 10 0 10 (POM molding to Test film) molding (N) Test 3 for adhesive property Adhesion strength to PE 0 140 72 123 55 (Test film to PE molding) molding (N) Test 4 for adhesive property Adhesion strength to PE 0 140 59 120 43 (PE molding to Test film) molding (N)

(125) From the results shown in Tables 1 to 4, any polyacetal resin composition obtained in Examples 1 to 15 met the passing criteria with respect to the adhesive property. On the contrary, each of the polyacetal resin compositions obtained in Comparative examples 1 to 11 did not meet the passing criteria with respect to the adhesive property.

(126) Accordingly, it was confirmed that the polyacetal resin composition of the present invention has excellent adhesive property with respect to any one of the polyacetal resin molding containing a polyacetal resin and the polyethylene resin molding containing a polyethylene resin.

EXPLANATIONS OF REFERENCE NUMERALS

(127) 10 Polyacetal resin molding

(128) 20 Polyethylene resin molding

(129) 30 Intermediate layer

(130) 100 Composite molding