POLYORGANOSILOXANE COMPOSITION FOR USE IN ADHESION OF A POLYPHENYLENE SULFIDE RESIN

Abstract

An addition reaction curing type polyorganosiloxane composition for bonding poly(phenylene sulfide) resins includes (A) a polyorganosiloxane containing two or more alkenyl groups in the molecule, (B) a polyorganohydrogensiloxane having, in the molecule, three or more silicon-atom-bonded hydrogen atoms, (C) a platinum-based catalyst, (D) an oxide or carbonate of a metal selected from among the metals in Groups 2 and 12 of the periodic table, and (E) an adhesion promoter, the content of the ingredient (D) being 0.1-20 wt % with respect to the whole composition.

Claims

1. A method of adhering a polyphenylene sulfide resin and a cured product of a polyorganosiloxane composition, the method comprising: applying the polyorganosiloxane composition to the polyphenylene sulfide resin; and curing the polyorganosiloxane composition resin; wherein the polyorganosiloxane composition comprises: (A) a polyorganosiloxane containing two or more alkenyl groups per molecule; (B) a polyorganohydrogensiloxane having three or more hydrogen atoms bonded to silicon atoms per molecule; (C) a platinum catalyst; (D) an oxide or carbonate of a metal selected from metals belonging to Groups 2 and 12 of the Periodic Table; and (E) an adhesion imparting agent, wherein the content of the component (D) in the whole composition is 0.1 to 20% by weight.

2. The method according to claim 1, wherein the component (D) is an oxide or carbonate of a metal selected from magnesium, calcium, and zinc.

3. The method according to claim 1, wherein the component (D) is zinc oxide.

4. The method according to claim 1, wherein the component (E) comprises at least one member selected from the group consisting of the following (E1) to (E4): (E1) an organosilicon compound having a hydrogen atom bonded to a silicon atom, and having a side chain of the following formula (1) bonded to a silicon atom: ##STR00012## (E2) an organosilicon compound having an Si(OR.sup.3).sub.n group and an epoxy group-containing group, and/or a partial hydrolysis condensation product thereof, (E3) a silane compound having an Si(OR.sup.3).sub.n group and an aliphatic unsaturated hydrocarbon group, and/or a partial hydrolysis condensation product thereof, and (E4) a tetraalkoxysilane compound represented by Si(OR.sup.4).sub.4, and/or a partial hydrolysis condensation product thereof, wherein, in the above formulae, Q.sup.1 represents a linear or branched alkylene group which forms a carbon chain having two or more carbon atoms between the silicon atom and the ester linkage; Q.sup.2 represents a linear or branched alkylene group which forms a carbon chain having three or more carbon atoms between the oxygen atom and the silicon atom of the side chain; R.sup.3 represents an alkyl group having 1 to 4 carbon atoms or a 2-methoxyethyl group; R.sup.4 represents an alkyl group having 1 to 3 carbon atoms; and n is an integer of 1 to 3.

5. The method according to claim 1, wherein the component (A) is a combination of (A1) a linear polyorganosiloxane having both ends blocked by an R.sub.3SiO.sub.1/2 unit and having an R.sup.2.sub.2SiO.sub.2/2 unit as an intermediate unit, and having a viscosity of 0.1 to 500 Pa.Math.s at 23° C., and (A2) a branched polyorganosiloxane comprising an SiO.sub.4/2 unit and an R.sub.3SiO.sub.1/2 unit and optionally further comprising at least one unit selected from the group consisting of an R.sub.2SiO.sub.2/2 unit and/or an RSiO.sub.3/2 unit, wherein, in the above formulae, R is R.sup.1 or R.sup.2, wherein R.sup.1 is an alkenyl group, R.sup.2 is a monovalent hydrocarbon group having no aliphatic unsaturated bond, and two or more R.sup.1,s are contained per molecule.

6. The method according o claim 1, wherein the component (C) is a platinum-vinylsiloxane complex.

7. The method according to claim 1, further comprising (F) a zirconium compound.

8. The method according to claim 1, further comprising (G) an inorganic filler having a BET specific surface area of 50 to 500 m2/g.

9. The method according to claim 1, further comprising (H) a reaction inhibitor.

10. An article obtained by the method according to claim 1 and comprising an adhesion portion of the polyphenylene sulfide resin and the cured product of the polyorganosiloxane composition.

Description

EXAMPLES

[0185] Hereinbelow, the present invention will be described in more detail with reference to the following Examples and Comparative Example. In the following Examples and Comparative Example, the “part(s)” indicates part(s) by weight, and the viscosity means a viscosity as measured at 23° C. The following Examples and Comparative Example should not be construed as limiting the scope of the present invention.

[0186] (Components Used)

[0187] The components used in the Examples and Comparative Example are as follows. [0188] (A) Alkenyl Group-Containing Polyorganosiloxane

[0189] A-1: Linear polymethylvinylsiloxane represented by M.sup.viD.sub.nM.sup.vi (wherein n is a value such that the polymethylvinylsiloxane has a viscosity of 10 Pa.Math.s at 23° C.)

[0190] A-2: Branched polymethylvinylsiloxane comprised only of an M unit, an M.sup.vi unit, and a Q unit, wherein the molar ratio of the units is represented by M.sub.5M.sup.viQ.sub.8 (weight average molecular weight: 4,000; four vinyl groups on average per molecule) [0191] (B) Polyorganohydrogensiloxane

[0192] B: Linear polymethylhydrogensiloxane (20 hydrogen atoms on average per molecule) being represented by MD.sup.H.sub.20D.sub.20M, and having a viscosity of 20 mPa.Math.s at 23° C. [0193] (C) Platinum Catalyst

[0194] C: Platinum-vinylsiloxane complex (Pt-M.sup.viM.sup.vi complex) which is obtained by heating chloroplatinic acid together with a siloxane dimer represented by M.sup.viM.sup.vi, and which has a platinum content of 2.0% by weight [0195] (D) Oxide or carbonate of a metal selected from metals belonging to Groups 2 and 12 of the Periodic Table

[0196] D-1: Calcium carbonate (NS#400, manufactured by Nitto Funka Kogyo K.K.; average particle diameter: 1.7 μm)

[0197] D-2: Magnesium oxide (PYROKISUMA 5301, manufactured by Kyowa Chemical Industry Co., Ltd.; average particle diameter: 2.0 μm)

[0198] D-3: Zinc oxide (Zinc white No. 1, manufactured by Mitsui Mining & Smelting Co., Ltd.; average particle diameter: 0.75 μm) [0199] (E) Adhesion Imparting Agent

[0200] E-1: Cyclic siloxane represented by the formula:

##STR00011##

[0201] E-2: 3 -Glycidoxypropyltrimethoxysilane

[0202] E-3: Vinyltrimethoxysilane

[0203] E-4: Partial hydrolysis condensation product (tetramer) of tetramethoxysilane (MKC (registered trademark) Silicate MS51, manufactured by Mitsubishi Chemical Corporation)

[0204] (F) Zirconium compound

[0205] F: (n-C.sub.41H.sub.9O).sub.3Zr(C.sub.5H.sub.7O.sub.2) Tributoxyzirconium acetylacetonate (ZC-540, manufactured by Matsumoto Fine Chemical Co., Ltd.); effective component: 45% by weight; metal content: 10.2% by weight [0206] (G) Inorganic filler having a BET specific surface area of 50 to 500 m.sup.2/g

[0207] G: Fumed silica having a specific surface area of 160 m.sup.2/g (Aerosil R-8200, manufactured by Nippon Aerosil Co., Ltd.) [0208] (H) Reaction Inhibitor

[0209] H: Diallyl maleate

Example 1

[0210] (1) Preparation of a First Portion

[0211] 47.0 Parts by weight of a solution which had been preliminarily prepared by dissolving A-2 in A-1 in a 1:1 weight ratio, 1.0 part by weight of D-1, and 18.0 parts by weight of G were transferred to a universal kneading machine (a planetary mixer), and stirred at room temperature (23° C.) for 60 minutes, and stirred under a reduced pressure at 150° C. for 60 minutes. The resultant mixture was cooled to 50° C. or lower, and 40.0 parts by weight of A-1 was added and the mixture was stirred for 30 minutes. C was added to the resultant mixture so that the amount of C became 100 ppm by weight, in terms of a platinum metal atom, based on the total weight of A-1 and A-2, and the mixture was stirred at room temperature for 10 minutes. 0.25 Part by weight of F was added and the mixture was stirred at room temperature for 10 minutes to prepare a “first portion”. The formulation of the first portion is shown in Table 1. [0212] (2) Preparation of a Second Portion

[0213] 47.0 Parts by weight of a solution which had been preliminarily prepared by dissolving A-2 in A-1 in a 1:1 weight ratio, 1.0 part by weight of D-1, and 18.0 parts by weight of G were transferred to a universal kneading machine (a planetary mixer), and stirred at room temperature (23° C.) for 60 minutes, and stirred under a reduced pressure at 150° C. for 60 minutes. The resultant mixture was cooled to 50° C. or lower, and 28.9 parts by weight of A-1 was added and the mixture was stirred for 30 minutes. 3.135 Parts by weight of B was added and the mixture was stirred at room temperature for 10 minutes. 0.03 Part by weight of H, 6.0 parts by weight of E-1, 0.88 part by weight of E-2, 1.0 part by weight of E-3, and 0.32 part by weight of E-4 were added and the mixture was stirred at room temperature for 10 minutes to prepare a “second portion”. The formulation of the second portion is shown in Table 2. [0214] (3) Preparation of a Polyorganosiloxane Composition (Mixture of the First Portion and the Second Portion)

[0215] The “first portion” and the “second portion”, which were prepared in advance, were mixed together, and subjected to deaeration by quickly kneading under a reduced pressure for 10 minutes, preparing a polyorganosiloxane composition (mixture of the first portion and the second portion). The H/Vi ratio in the composition was 0.60.

Examples 2 to 6

[0216] A “first portion” and a “second portion” were prepared in substantially the same manner as in Example 1 except that the type and amount of component D were changed, and polyorganosiloxane compositions in Examples 2 to 6 were prepared. The formulation of the first portion and the formulation of the second portion in Examples 2 to 6 are respectively shown in Table 1 and Table 2.

Comparative Example 1

[0217] A “first portion” and a “second portion” were prepared in substantially the same manner as in Example 1 except that component D was not incorporated, and a polyorganosiloxane composition in Comparative Example 1 was prepared. The formulation of the first portion and the formulation of the second portion in Comparative Example 1 are respectively shown in Table 1 and Table 2.

[0218] (Evaluation Method)

<Preparation of a Test Specimen>

[0219] A test specimen for an adhesion test under shear was prepared in accordance with JIS K6249:2003 as described below. Specifically, the procedure was as follows.

[0220] With respect to each of the compositions in Examples 1 to 6 and Comparative Example 1, a caulking cartridge was filled with the composition. Two resin plates (80 mm×25 mm×2 mm) of a polyphenylene sulfide resin (SUSTEEL (registered trademark) GS-40%, manufactured by Tosoh Corporation) were prepared. The composition was applied to one surface of one of the resin plates by extruding the composition from the caulking cartridge so that the application length from one short side became 10 mm, the applied portion had a size of 25 mm×10 mm, and the thickness became 1.0 mm. Another resin plate was stacked from one short side on the potion to which the composition was applied so that the adhesion portion had a size of 25 mm×10 mm, and the stacked portions of the resin plates were fixed using a jig. The thus fixed resin plates were heated at 50° C. for 30 minutes to cure the composition so as to bring adhesion between the resin plates, obtaining a test specimen.

[0221] <150° C. Storage Test>

[0222] Test specimens for an adhesion test under shear were individually subjected to accelerated test in a hot-air-circulating dryer at 150° C. for 250, 500, and 1,000 hours, and subjected to the below-described adhesion test under shear and evaluation of cohesive failure rate.

[0223] <Adhesion Test Under Shear>

[0224] With respect to each of the test specimen obtained after one day from the preparation as a specimen for initial evaluation, and the test specimens obtained after subjected to accelerated test at 150° C. for 250, 500, and 1,000 hours, an adhesive force under shear was evaluated in accordance with JIS K6249:2003. The rate of pulling was 10 mm/min.

[0225] <Evaluation of Cohesive Failure Rate>

[0226] With respect to the test specimen which had been subjected to adhesion test under shear, the adhered surface of the test specimen was observed, and a proportion of the area of the cured product adhering on the polyphenylene sulfide resin to the whole adhered area was determined and evaluated as a cohesive failure rate. The determined cohesive failure rate was a value that increases or decreases by 10%. The larger the cohesive failure rate, the stronger the adhesion of the interface between the polyphenylene sulfide resin and the cured product of the composition.

[0227] With respect to the test specimens prepared using the compositions in Examples 1 to 6 and Comparative Example 1, the results of the measurement of the initial adhesive force under shear and cohesive failure rate and those after stored at 150° C. are shown in Table 3.

TABLE-US-00001 TABLE 1 Comparative Raw materials Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 1 A-1 M.sup.viD.sub.nM.sup.vi (Viscosity: 10 Pa .Math. s) 63.5 63.5 63.5 63.5 63.5 63.5 63.5 A-2 M.sub.5M.sup.ViQ.sub.8 23.5 23.5 23.5 23.5 23.5 23.5 23.5 C Pt—M.sup.viM.sup.vi Complex (Pt Content: 2.0 wt %) 100 ppm 100 ppm 100 ppm 100 ppm 100 ppm 100 ppm 100 ppm D-1 CaCO.sub.3 1.0 5.0 D-2 MgO 1.0 5.0 D-3 ZnO 1.0 5.0 F (n-C.sub.4H.sub.9O).sub.3Zr(C.sub.5H.sub.7O.sub.2) 0.25 0.25 0.25 0.25 0.25 0.25 0.25 G Aerosil R-8200 18.0 18.0 18.0 18.0 18.0 18.0 18.0 Total 106.25 110.25 106.25 110.25 106.25 110.25 105.25

[0228] The formulation for C is a value, in terms of a platinum metal atom, based on the total weight of A-1 and A-2.

TABLE-US-00002 TABLE 2 Comparative Raw materials Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 1 A-1 M.sup.viD.sub.nM.sup.vi (Viscosity: 10 Pa .Math. s) 52.4 52.4 52.4 52.4 52.4 52.4 52.4 A-2 M.sub.5M.sup.ViQ.sub.8 23.5 23.5 23.5 23.5 23.5 23.5 23.5 B MD.sup.H.sub.20D.sub.20M 3.135 3.135 3.135 3.135 3.135 3.135 3.135 D-1 CaCO.sub.3 1.0 5.0 D-2 MgO 1.0 5.0 D-3 ZnO 1.0 5.0 E-1 Cyclic siloxane 6.0 6.0 6.0 6.0 6.0 6.0 6.0 E-2 3-Glycidoxypropyltrimethoxysilane 0.88 0.88 0.88 0.88 0.88 0.88 0.88 E-3 Vinyltrimethoxysilane 1.0 1.0 1.0 1.0 1.0 1.0 1.0 E-4 Partial hydrolysis condensation product 0.32 0.32 0.32 0.32 0.32 0.32 0.32 (tetramer) of tetramethoxysilane G Aerosil R-8200 18.0 18.0 18.0 18.0 18.0 18.0 18.0 H Diallyl maleate 0.03 0.03 0.03 0.03 0.03 0.03 0.03 Total 106.265 110.265 106.265 110.265 106.265 110.265 105.265

TABLE-US-00003 TABLE 3 Comparative Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 1 Initial Adhesive force under shear MPa 1.84 1.76 1.72 1.68 1.60 1.80 1.82 Cohesive failure rate % 100 100 100 100 100 100 100 Stored  250 hr Adhesive force under shear MPa 2.27 2.65 1.83 2.54 2.81 3.38 1.36 at 150° C. Cohesive failure rate % 90 100 30 100 100 100 20  500 hr Adhesive force under shear MPa 2.34 3.05 1.90 2.88 3.03 3.85 1.96 Cohesive failure rate % 40 100 20 90 100 100 10 1000 hr Adhesive force under shear MPa 1.41 2.55 1.10 1.76 2.19 2.68 0.91 Cohesive failure rate % 20 80 10 40 100 100 5

[0229] As apparent from Table 3, the polyorganosiloxane compositions in Examples 1 to 6 have not only excellent initial adhesion to the polyphenylene sulfide resin but also a small lowering of the adhesion after stored at 150° C.

[0230] A comparison made between Examples 1 and 2, Examples 3 and 4, and Examples 5 and 6 shows that, in the order of zinc oxide, calcium carbonate, and magnesium oxide, component D is excellent and causes a small lowering of the cohesive failure rate after stored at 150° C. Further, a comparison made between Examples 1, 3, and 5 and Examples 2, 4, and 6 shows that Examples 2, 4, and 6, in which the amount of the incorporated component D is 5.0 parts by weight, are excellent such that a lowering of the cohesive failure rate after stored at 150° C. is small.

[0231] In Example 5 in which zinc oxide is used as component D, despite the amount of the incorporated component D which is as small as 1.0 part by weight, the adhesive force under shear after subjected to accelerated test at 150° C. for 1,000 hours was high, and 100% of the cohesive failure rate was maintained, and thus the adhesion to the polyphenylene sulfide resin after stored at 150° C. was excellent.

[0232] The composition in Comparative Example I does not contain component D, and hence had excellent initial adhesion to the polyphenylene sulfide resin, but was markedly lowered in the adhesive force under shear and cohesive failure rate after subjected to accelerated test at 150° C. even for 250 hours.

Industrial Applicability

[0233] The polyorganosiloxane composition of the present invention for use in adhesion of a polyphenylene sulfide resin can be used as an adhesive for parts exposed to a high temperature environment, such as electric or electronic parts and automobile parts.