POLYVINYL AROMATE-POLYDIENE-BLOCK COPOLYMER-BASED ADHESIVE COMPOUNDS HAVING IMPROVED THERMAL SHEAR STRENGTH

Abstract

The invention relates to polyvinal aromate-polydiene-block copolymer-based adhesive compounds that contain at least one type of a cationically curable reactive resin and that result, when cured, in improved thermal shear strength. The invention further relates to adhesive strips that contain at least one layer of such an adhesive compound, and a method of production.

Claims

1. Pressure sensitive adhesive comprising a) a base formulation containing (i) 25 to 45 wt % of at least one elastomer component containing at least one polyvinylaromatic-polydiene block copolymer, where the polyvinylaromatic-polydiene block copolymer at least fractionally has an A-B-A, (A-B).sub.nX or (A-B-A).sub.nX structure, in which the blocks A independently of one another are a polymer formed by polymerisation of at least one vinylaromatic, the blocks B independently of one another are a polymer formed by polymerisation of conjugated dienes having 4 to 18 carbon atoms or are a derivative of such a polymer that is partially hydrogenated in the polydiene block, X is the residue of a coupling reagent or initiator and n is an integer ?2, where the peak molar mass of the at least one polyvinylaromatic polydiene block copolymer according to Test IVa is at least 160 000 g/mol, where the fraction of A blocks in the at least one polyvinylaromatic polydiene block copolymer is at least 8 wt % and at most 25 wt % and where optionally there may be a fraction of diblock copolymer A-B, containing blocks A and B as defined above, of at most 25 wt %, based on the total elastomer component, (ii) 33 to 55 wt % of at least one tackifier resin component with at least one tackifier resin, where the at least one tackifier resin has a softening temperature (Ring & Ball, Test VII) of ?80? C., and (iii) 13 to 30 wt % of at least one reactive resin component containing at least 70 wt % of at least one reactive resin based on a cyclic ether having a dispersive component of the Hansen parameter, ?.sub.D, of 17.50 to 17.82 MPa.sup.1/2, based in each case on the base formulation, where the sum of the elastomer component and the reactive resin component is at least 38 wt % and at most 68 wt %, b) 0.1 to 5 wt %, based on the amount of reactive resin component, of at least one initiator for the cationic curing of the at least one reactive resin, c) optionally at least one plasticizer, and d) optionally at least one additive.

2. Pressure sensitive adhesive according to claim 1, wherein the polyvinylaromatic-polydiene block copolymer is a polystyrene-polybutadiene block copolymer, a polystyrene-polyisoprene block copolymer, or a polystyrene-polyfarnesene block copolymer.

3. Pressure sensitive adhesive according claim 1, wherein the polyvinylaromatic-polydiene block copolymer is a mixture of (i) triblock copolymer A-B-A or (A-B).sub.2X and (ii) radial (A-B).sub.nX block copolymer in which n is an integer ?3.

4. Pressure sensitive adhesive according to claim 1, wherein the dispersive component of the Hansen parameter, ?.sub.D, of the reactive resin differs by at most 2 MPa.sup.1/2 from the dispersive component of the Hansen parameter, ?.sub.D, of the polyvinylaromatic of the at least one polyvinylaromatic-polydiene block copolymer.

5. Pressure sensitive adhesive according to claim 1, wherein the at least one reactive resin based on a cyclic ether is an epoxide or an oxetane.

6. Pressure sensitive adhesive according to claim 5, wherein the reactive resin based on a cyclic ether is aliphatic or cycloaliphatic in nature.

7. Pressure sensitive adhesive according to claim 1, wherein the initiator is selected from thermally activatable initiators for initiating a cationic curing, radiochemical initiators for initiating a cationic curing, and also mixtures of these.

8. Cured pressure sensitive adhesive obtainable or obtained by curing a pressure sensitive adhesive according to claim 1.

9. Adhesive tape which comprises at least one layer of a pressure sensitive adhesive according to claim 1.

10. Adhesive tape according to claim 9, which is an adhesive transfer tape.

11. Adhesive tape according to claim 9, wherein the adhesive tape comprises at least one carrier bearing on at least one side an applied layer of the pressure sensitive adhesive or of a cured pressure sensitive adhesive obtainable or obtained by curing the pressure sensitive adhesive.

12. Adhesive tape according to claim 11, wherein the carrier is a foam carrier.

13. Process for producing an adhesive tape according to claim 9, comprising coating and drying a solvent-borne adhesive, wherein thermal curing of the adhesive takes place or is initiated during the drying.

14. Process according to claim 13, in which at least one solvent is used which at a pressure of 1013 mbar has a boiling point of at least 75? C. and also has a Hildebrand parameter of greater than 7.5 cal.sup.1/2 cm.sup.?3/2 and less than 10 cal.sup.1/2 cm.sup.?3/2.

Description

EXAMPLES

[0131] In the invention and comparative examples, percentages refer to wt %, unless otherwise indicated. The formulation constituents add up in each case to 100 wt % with solvent being disregarded. Differing from this, figures for the amount of initiator used are based on the amount of reactive resin component used.

[0132] Raw Materials:

[0133] Raw materials used in the inventive and comparative examples were as follows (Table 3).

TABLE-US-00003 TABLE 3 Raw materials used in the inventive and comparative examples. Elastomer Europrene Sol T6414 Polystyrene- PS content: 40 wt % radial component (Versalis) polybutadiene diblock content: 22 wt % block copolymers M.sub.P: 116 000 g/mol Globalprene 3522 Polystyrene- PS content: 23 wt % triblock (LCY) polybutadiene diblock content: 78 wt % block copolymers M.sub.P:170 000 g/mol Kraton D1116 Polystyrene- PS content: 23 wt %* radial (Kraton Performance polybutadiene diblock content 16 wt % Polymers) block copolymers M.sub.P: 300 000 g/mol Kraton D1124 Polystyrene- PS content: 30% radial (Kraton Performance polyisoprene diblock content: 30 wt % Polymers) block copolymers M.sub.P: 180 000 g/mol Kraton D1126 Polystyrene- PS content: 19 wt % radial (Kraton Performance polyisoprene diblock content: 30 wt % Polymers) block copolymers M.sub.P: 155 000 g/mol Kraton HT1200 Polystyrene- PS content: 10 wt % radial (Kraton Performance polyisoprene diblock content: 15 wt % Polymers) block copolymers M.sub.P: 658 000 g/mol Solprene S416 Polystyrene- PS content: 30 wt % radial (Dynasol) polybutadiene diblock content < 10 wt % block copolymers M.sub.P: 207 000 g/mol Tufprene 315P Polystyrene- PS content: 20 wt % triblock (Asahi Kasei) polybutadiene diblock content < 5 wt % block copolymers M.sub.P: 106 000 g/mol Vector 4113 Polystyrene- PS content: 15 wt % triblock (TSRC) polyisoprene diblock content: 18 wt % block copolymers M.sub.P : 190 000 g/mol Tackifier Piccolyte A115 Alpha pinene resin Softening point: 115? C. resin (DRT) DACP = +35? C. component Regalite R1090 Fully hydrogenated Softening point: 90? C. (Eastman Chemical) C9 hydrocarbon DACP = +55? C. resin Reactive 3,4-Epoxycyclohexyl- Cycloaliphatic ?.sub.D = 17.74 MPa.sup.0.5 resin methyl 3,4-epoxy- diepoxide component cyclohexanecarboxy- late (Uvacure 1500, Allnex) Bis((3,4-Epoxycyclo- Cycloaliphatic ?.sub.D = 17.6 MPa.sup.0.5 hexyl)methyl) adipate diepoxide (Sigma Aldrich) Dicyclopentadiene Cycloaliphatic ?.sub.D = 17.84 MPa.sup.0.5 diepoxide (Sigma diepoxide Aldrich) 1,5-Hexadiene Aliphatic diepoxide ?.sub.D = 17.3 MPa.sup.0.5 diepoxide (Sigma Aldrich) Diglycidyl-1,2-cyclo- Cycloaliphatic ?.sub.D = 17.6 MPa.sup.0.5 hexane dicarboxylate diepoxide (Sigma Aldrich) Neopentyl glycol Aliphatic diepoxide ?.sub.D = 17.64 MPa.sup.0.5 diglycidylether (Sigma Aldrich) Perhydrobisphenol Hydrogenated ?.sub.D = 17.42 MPa.sup.0.5 A diglycidyl ether aromatic diepoxide (ER15, IPOX) 4,4-Isopropylidene- Aromatic diepoxide ?.sub.D = 18.9 MPa.sup.0.5 diphenol-epichloro- hydrin (Epikote 828, Hexion Specialty Chemicals) Curing K-Pure CXC 1613 Thermal initiator (a component (King Industries) Zn triflate), in the form of a 25 wt % strength solution in 2-butanol p-Methoxybenzyl- Thermal initiator tetrahydrothio- phenium hexafluoro- antimonate (UVC 531, Synlab GmbH Friesoithe) Irgacure 290 Sulfonium-based (BASF SE) photoinitiator Further Wingtack 10 C.sub.5 plasticizer compounds (Cray Valley) resin used Expancel 920 Expandible DUT40 (Nouryon) microballoons

[0134] Production and Properties of the Adhesive Tape Specimens:

[0135] For the production of the adhesive tape specimens of Examples I1 to I18 and comparative Examples C1 to C22, all of the formulation constituents required in each case (as set out in Table 3) were dissolved in a solvent mixture of ethyl acetate/toluene/benzine (14 wt % 30 wt %/56 wt %). The initiator was added either as supplied (K-Pure CXC 1613 solution) or in an in-house dissolved form (UVC 531 or Irgacure 290, each as a 33 wt % strength solution in methyl ethyl ketone) and incorporated for 30 min using a propeller stirrer. The solvent content in the resultant solution was 40 wt % in each case. Each solution was then coated onto a siliconized PET film.

[0136] The specimens were initially dried for 10 min at room temperature and then dried for 15 min at 120? C., unless otherwise indicated. After the drying, or drying and foaming, the adhesive film thickness of the coats was 50 ?m (within the bounds of the usual error margins). After 24 h, the adhesive tape specimens were evaluated. Details of the investigations can be found in particular in the Test Methods Section.

I: Comparative Examples C1 to C22

[0137] a) Formula Optimisation:

[0138] In comparative Examples C1 to C10, the amounts used of the constituents of the base formulation, i.e. of the elastomer component, the tackifier resin component and the reactive resin component, and also of the initiator for the cationic curing of the reactive resin, were varied with the objective of optimising the thermal shear strength (SAFT) and peel adhesion on steel. The composition of the adhesive tapes from comparative Examples C1 to C10 and their properties are shown in Table 4.

TABLE-US-00004 TABLE 4 Composition and properties of the adhesive tapes from comparative Examples C1 to C10. Peel adhe- Global- K- sion Kraton Prene Piccolyte Uvacure Pure Steel Ex. D1116 3522 A115 1500 CXC SAFT (N/ (comp.) (wt %) (wt %) (wt %) (wt %) 1613? (? C.) cm) C1 50 0 50 0 0 139 8.4 C2 26 0 54 20 0 98 0.8 C3 25 0 65 10 3 103 5.7 C4 35 0 53 12 3 127 12.55 C5 30 15 40 15 3 129 6.8 C6 45 0 48 7 3 132 9.3 C7 35 10 40 15 3 134 6.5 C8 50 0 50 0 3 140 9.6 C9 30 0 35 35 3 210 0.1 C10 50 0 30 20 3 213 1.7 .sup.aFraction of K-Pure CXC 1613 solution in wt % based on the amount of reactive resin Uvacure 1500.

[0139] C1 shows a blend without Uvacure 1500 and thus without epoxide curing. A SAFT result of higher than 140? C. cannot be achieved here.

[0140] C2 shows additionally that the epoxide cannot react with thermal self-curing, since no initiator is present. The epoxide does not cure, and so the thermal stability is even poorer than for comparative formula C1. The epoxide here acts as a plasticizer.

[0141] C3 to C7 make it clear in particular that with regard to the fractions of the individual components there is only one specific corridor within which both an acceptable peel adhesion result and an outstanding thermal stability can be achieved. All results with these raw materials combinations exhibit a thermal shear strength which is too low.

[0142] C8 shows that the initiator on its own does not exert any effect on the achievement of the performance requirement.

[0143] C9 and C10 show, moreover, that too high a fraction of cured reactive resin leads to a sharp reduction in the peel adhesion, causing the adhesive tape to lose its pressure sensitive adhesive character.

[0144] b) Elastomer Screening:

[0145] In comparative Examples C11 to C15, the selected elastomer was varied. As well as 40 wt % of the respective elastomer, respectively 40 wt % of tackifier resin (Piccolyte A 115), 20 wt % of reactive resin (Uvacure 1500) and 3 wt % of initiator solution (K-Pure CXC 1613 solution), based on the amount of Uvacure 1500, were used. Table 5 shows the particular elastomer used and the SAFT temperature of the resultant adhesive tapes. Also reported, moreover, is the SAFT temperature produced when the reactive resin Uvacure 1500 is omitted from each adhesive formulation (with the amounts of the further constituents used remaining unchanged).

TABLE-US-00005 TABLE 5 Elastomers used in comparative Examples C11 to C15 and SAFT values of the resultant adhesive tapes. Diblock PS Ex. Polymer fraction content SAFT SAFT (Comp.) Elastomer type (wt %) (wt %) Architecture (? C.).sup.a (? C.).sup.b C11 Solprene PS poly- <10 30 Radial 98 131 S416 butadiene C12 Kraton PS-poly- 30 19 Radial 100 104 D1126 isoprene C13 Tufprene PS-poly- <5 20 Linear 95 98 315P butadiene (triblock) C14 Europrene PS-poly- 22 40 Radial 97 118 Sol T butadiene 6414 C15 Kraton PS-poly- 30 30 Radial 90 119 D1124 isoprene ?with Uvacure 1500; .sup.bwithout Uvacure 1500.

[0146] C11 to C15 show that there is only a small properties corridor for the elastomers within which epoxide compatibility of the polystyrene domains can be achieved.

[0147] c) Epoxide Screening:

[0148] In comparative Examples C16 to C22, the selected epoxide, i.e. reactive resin, was varied. As well as 20 wt % of the respective epoxide, respectively 40 wt % of elastomer (Kraton D1116), 40 wt % of tackifier resin (Piccolyte A 115), and 3 wt % of initiator solution (K-Pure CXC 1613 solution), based on the amount of epoxide, were used. Table 6 shows the particular epoxide used and the SAFT temperature of the resultant adhesive tapes.

[0149] C16 to C22 set out the important part played by the solubility of the epoxide in terms of its effect on the achievement of the performance requirement.

TABLE-US-00006 TABLE 6 epoxide (reactive resin) used in comparative Examples C16 to C22 and SAFT values of the resultant adhesive tapes. Ex. SAFT (comp.) Epoxide (? C.) C16 Bis((3,4-epoxycyclohexyl)methyl) adipate 118 C17 1,5-Hexadiene diepoxide 113 C18 Diglycidyl 1,2-cyclohexanedicarboxylate 110 C19 Neopentyl glycol diglycidyl ether 113 C20 Dicyclopentadiene diepoxide 105 C21 Perhydrobisphenol A diglycidyl ether 98 C22 4,4-Isopropylidenediphenol-epichlorohydrin 108

II: Inventive Examples I1 to I18

[0150] a) Inventive PSAs Based on Polystyrene-Polybutadiene Block Copolymers:

[0151] Table 7 shows the quantitative composition of the inventive adhesive tapes from Examples 11 to 114, whose elastomer in each case is a polystyrene-polybutadiene block copolymer in the form of Kraton D1116, and their properties.

TABLE-US-00007 TABLE 7 Composition of the inventive adhesive tapes from Examples I1 to I14 and their properties. Peel Kraton Piccolyte Uvacure Wing- K-Pure adhe- D1116 A115 1500 tack 10 CXC SAFT sion Ex. (wt %) (wt %) (wt %) (wt %) 1613? (? C.) (N/cm) I1 42 45 13 0 3 150 8.7 I2 42 40 13 5 3 153 7.2 I3 35 45 15 5 3 156 11.4 I4 35 50 15 0 3 160 13.3 I5 41 40 14 5 3 161 7.3 I6 26 54 20 0 3 165 12.03 I7 29.5 50 20 0 3 183 14.3 I8 35 40 20 5 3 196 8.7 I9 35 45 20 0 3 200 10.2 I10 43 37 20 0 3 221 5.6 I11 45 35 20 0 3 240 5.0 I12 33.5 46.5 20 0 3 210 10.0 I13 40 40 20 0 3 180 6.5 I14 40 40 20 0 1.5.sup.b 180 6.5 ?Fraction of K-Pure CXC 1613 solution in wt % based on the amount of reactive resin Uvacure 1500. .sup.bInstead of 3 wt % of K-Pure CXC 1613 solution, 1.5 wt % of UVC 531 solution was used here, again based on the amount of Uvacure 1500.

[0152] Examples I1 to I14 show in particular that an inventive fraction of inventive reactive resin in a polystyrene-polybutadiene block copolymer matrix leads after curing to a high thermal shear strength, but at the same time also meets the requirements for good peel adhesion.

[0153] b) Inventive PSAs Based on Polystyrene-Polyisoprene Block Copolymers:

[0154] Table 8 shows the quantitative composition of the inventive adhesive tapes from Examples I15 and I16, whose elastomer is in each case a polystyrene-polyisoprene block copolymer in the form of Vector 4113, and their properties.

TABLE-US-00008 TABLE 8 Composition of the inventive adhesive tapes from Examples I15 and I16 and their properties. Peel Vector Regalite Uvacure K-Pure adhesive 4113 R1090 1500 CXC SAFT Steel Ex. (wt %) (wt %) (wt %) 1613? (? C.) (N/cm) I15 40 40 20 3 160 6.1 I16 45 35 20 3 167 4.3 .sup.aFraction of K-Pure CXC 1613 solution in wt % based on the amount of Uvacure 1500.

[0155] Examples I15 and I16 show that this concept can also be applied to polystyrene-polyisoprene block copolymer as a matrix polymer.

[0156] c) Inventive PSA Containing Photoinitiator:

[0157] A further adhesive tape, 117, was produced from 40 wt % of Kraton HT1200 as elastomer, 40 wt of Regalite R1090 as tackifier resin and 20 wt % of Uvacure 1500 as reactive resin, with a thermal initiator being replaced by the use of a photoinitiator in the form of 9 wt % of Irgacure 290 solution, based on the reactive resin Uvacure 1500. The adhesive tape was produced as for the thermally cured adhesive tapes, with the curing taking place by subsequent irradiation with UV light on an Eltosch belt unit with a belt speed of 4 m/min, using a mercury-doped UV lamp with an output of 160 W/cm.

[0158] The resultant adhesive tape has a SAFT temperature of 212? C. and a peel adhesion on steel of 5.1 N/cm. Example 117 shows that curing can be carried out with a photoinitiator as well, instead of a thermal initiator.

[0159] d) Inventive PSA Foamed with Microballoons:

[0160] The production of adhesive tape I18 differs from the production of adhesive tape I13 in that the adhesive solution, before being coated onto a siliconised PET film, was admixed with 1.5 wt % of Expancel 920 DUT40 expandible microballoons, the microballoons being used in the form of a suspension in benzine. The weight fractions for the microballoons are based here on the dry weight of the solution used, to which they were added (i.e. the dry weight of the solution used is set at 100%). The initial drying for 10 min at room temperature and drying for 15 min at 100? C. produce an as yet unfoamed adhesive tape. The open side of the adhesive tape was then lined with a further ply of a siliconized PET film, and the adhesive tape was foamed for 1 min at 170? C.

[0161] The foamed adhesive tape has a SAFT temperature of 180? C. and a peel adhesion on steel of 5.7 N/cm. Example 118 shows that even adhesive tapes foamed with microballoons are able to have the desired profile of properties, such as, in particular, a high thermal shear strength.

Test Methods

[0162] All measurements were carried out, unless otherwise indicated, at 23? C. and 50% relative humidity.

[0163] The mechanical and technical adhesive data were ascertained as follows:

Test 1Thermal Shear Strength (SAFT)

[0164] This test serves for rapid testing of the shear strength of adhesive tapes under temperature load. For this purpose, the adhesive tape under investigation is bonded to a temperature-controllable steel plate and loaded with a weight (50 g) and the shear distance is recorded.

[0165] Sample Preparation:

[0166] The adhesive tape under investigation (50 ?m transfer tape) is bonded by one of the adhesive sides to an aluminium foil 50 ?m thick. The adhesive tape thus prepared is cut to a size of 10 mm*50 mm.

[0167] The trimmed adhesive tape is bonded by the other adhesive side to a polished steel test plate cleaned with acetone (material 1.4301, DIN EN 10088-2, surface 2R, surface roughness Ra=30 to 60 nm, dimensions 50 mm*13 mm*1.5 mm), the bond being made such that the bond area of the sample in terms of height*width=13 mm*10 mm and the steel test plate protrudes by 2 mm at the upper edge. A 2 kg steel roller is subsequently rolled over the bond six times at a speed of 10 m/min for fixing it. The sample is reinforced flush at the top with a stable adhesive strip which serves as a contact point for the distance sensor. The sample is then suspended by means of the steel plate such that the longer-protruding end of the adhesive tape points vertically downwards.

[0168] Measurement:

[0169] The sample for measurement is loaded at the bottom end with a weight of 50 g. The steel test plate with the bonded sample is heated, starting at 25? C. at a rate of 9 K/min, to the final temperature of 200? C.

[0170] The distance sensor is used to observe the slip distance of the sample as a function of temperature and time. The maximum slip distance is set at 1000 ?m (1 mm); if exceeded, the test is discontinued and the failure temperature is noted. Test conditions: room temperature 23+/?3? C., relative humidity 50+/?5%. The result is reported as the mean value from two individual measurements, in ? C.

Test IIPeel Adhesion

[0171] The investigation takes place in accordance with PSTC-1. A strip 2 cm wide and 15 cm long of the adhesive tape specimen with a thickness of 50 ?m is lined on one of its adhesive sides with a PET film 25 ?m thick and bonded by the other adhesive tape side to a polished steel plate (ASTM). A defined bond is ensured by rolling over the bond back and forth five times with a 4 kg roller. The plate is clamped in and the self-adhesive strip is peeled off via its free end on a tensile testing machine at a peel angle of 180? and at a speed of 300 mm/min. The test conditions are 23? C.+/?3? C./50%+/?5% r.H. The result reported is the mean value from three individual measurements, in N/cm.

Test IIIGlass Transition Temperature of Polymer Blocks, DSC

[0172] The glass transition temperature of polymer blocks in block copolymers is determined by means of dynamic scanning calorimetry (DSC). For this determination, around 5 mg of the untreated block copolymer samples are weighed into a small aluminium crucible (volume 25 ?l) and closed with a perforated lid. Measurement takes place using a DSC 204 F1 from Netzsch, operating under nitrogen for inertness. The sample is first cooled to ?150? C., heated to +150? C. at a heating rate of 10 K/min, and cooled again to ?150? C. The subsequent, second heating curve is run again at 10 K/min and the change in the heat capacity is recorded. Glass transitions are recognised as steps in the thermogram. The glass transition temperature is evaluated as follows: A tangent is applied in each case to the baseline of the thermogram before 1 and after 2 of the step. In the region of the step, a line 3 of best fit is placed parallel to the ordinate in such a way as to intersect the two tangents, specifically so as to form two areas 4 and 5 (between the respective tangent, the line of best fit, and the measurement plot), of equal area. The point of intersection of the line of best fit positioned accordingly and the measurement plot gives the glass transition temperature.

Test IVMolar Mass, GPC

[0173] (a) Peak Molar Mass of Individual Block Copolymer Modes:

[0174] GPC is appropriate as a metrological method for determining the molar mass of individual polymer modes in mixtures of different polymers. For the block copolymers which can be used for the purposes of this invention, produced by living anionic polymerisation, the molar mass distributions are typically narrow enough to allow polymer modeswhich can be assigned to triblock copolymers, diblock copolymers or multiblock copolymersto appear with sufficient resolution from one another in the elugram. It is then possible to read off the peak molar mass for the individual polymer modes from the elugrams.

[0175] Peak molar masses M.sub.P are determined by gel permeation chromatography (GPC). The eluent used is THF. The measurement is made at 25? C. The pre-column used is PSS-SDV, 10?, ID 8.0 mm?50 mm. For separation, the columns used are PSS-SDV, 10?, 10.sup.3 ? and also 10.sup.5 ? and 10.sup.6 ? each with ID 8.0 mm?300 mm. The sample concentration is 3 g/l, the flow rate 1.0 ml per minute. Measurement is made against PS standards. Calibration is carried out using the commercially available ReadyCal kit Poly(styrene) high from PSS Polymer Standard Service GmbH, Mainz, (?=?m; 1 ?=10.sup.?10 m).

[0176] (b) Weight-Average Molar Mass, Especially of Tackifier Resins:

[0177] The weight-average molecular weight M.sub.w (M.W.) is determined by gel permeation chromatography (GPC). The eluent used is THF. The measurement is made at 25? C. The pre-column used is PSS-SDV, 10?, ID 8.0 mm?50 mm. For separation, the columns used are PSS-SDV, 10?, 10.sup.3 ? and also 10.sup.4 ? and 10.sup.6 ? each with ID 8.0 mm?300 mm. The sample concentration is 3 g/l, the flow rate 1.0 ml per minute. Measurement is made against PS standards. Calibration is carried out using the commercially available ReadyCal kit Poly(styrene) high from PSS Polymer Standard Service GmbH, Mainz, (?=?m; 1 ?=10.sup.?10 m).

Test VResin Compatibility, DACP

[0178] 5.0 g of test substance (the tackifying resin specimen under investigation) are weighed out into a dry test tube, and 5.0 g of xylene (isomer mixture, CAS [1330-20-7], ?98.5%, Sigma-Aldrich #320579 or comparable) are added. The test substance is dissolved at 130? C. and the solution is then cooled to 80? C. Any xylene that has escaped is made up for with further xylene, so that 5.0 g of xylene are again present. Then 5.0 g of diacetone alcohol (4-hydroxy-4-methyl-2-pentanone, CAS [123-42-2], 99%, Aldrich #H41544 or comparable) are added. The test tube is shaken until the test substance has fully dissolved. For this, the solution is heated to 100? C. The test tube containing the resin solution is then introduced into a Novomatics Chemotronic Cool cloud point measuring instrument in which it is heated to 110? C. Cooling is carried out at a cooling rate of 1.0 K/min. The cloud point is detected optically. For this, the temperature at which the turbidity of the solution is 70% is registered. The result is reported in ? C. The lower the DACP, the higher the polarity of the test substance.

Test VIResin Compatibility, MMAP

[0179] 5.0 g of test substance (the tackifying resin specimen under investigation) are weighed out into a dry test tube, and 10 ml of dry aniline (CAS [62-53-3], ?99.5%, Sigma-Aldrich #51788 or comparable) and 5 ml of dry methylcyclohexane (CAS [108-87-2], ?99%, Sigma-Aldrich #300306 or comparable) are added. The test tube is shaken until the test substance has fully dissolved. For this, the solution is heated to 100? C. The test tube containing the resin solution is then introduced into a Novomatics Chemotronic Cool cloud point measuring instrument in which it is heated to 110? C. Cooling is carried out at a cooling rate of 1.0 K/min. The cloud point is detected optically. For this, the temperature at which the turbidity of the solution is 70% is registered. The result is reported in ? C. The lower the MMAP, the higher the aromaticity of the test substance.

Test VIIResin Softening Temperature

[0180] The determination of the tackifier resin softening temperature is carried out according to the relevant methodology, which is known as Ring & Ball and is standardised according to ASTM E28.