WEATHERING-RESISTANT ADHESIVE WITH GOOD WET-OUT CAPACITY, AND ADHESIVE TAPES BASED THEREON

Abstract

Disclosed is an adhesive composition comprising: (a) at least one kind of a saturated vinylaromatic block copolymer, (b) at least one kind of a first tackifier resin, which is a hydrocarbon resin having a DACP+25 C. and an MMAP+60 C., and also either (c1) at least one kind of a second tackifier resin, having a DACP0 C. and an MMAP+30 C., and (d1) at least one kind of an aliphatic or cycloaliphatic alkyl ester as a plasticizer, or (c2) at least one kind of a second tackifier resin, having a DACP0 C. and an MMAP+30 C., and (d2) at least one kind of an aliphatic or cycloaliphatic alkyl ester as a plasticizer, and also (e) optionally further additives. The adhesive composition combines high ageing stability with exceptional aptitude for bonding on porous and also on fibrous materials.

Claims

1. Adhesive composition comprising: (a) about 25 wt % to about 50 wt % of at least one kind of a saturated vinylaromatic block copolymer, (b) about 20 wt % to about 50 wt % of at least one kind of a first tackifier resin, which is a hydrocarbon resin, having a DACP of more than +25 C. and an MMAP of more than +60 C., and also either (c1) 0 wt % to about 10 wt % of at least one kind of a second tackifier resin, having a DACP of less than 0 C. and an MMAP of less than +30 C., and (d1) about 5 wt % to about 25 wt % of at least one kind of an aliphatic or cycloaliphatic alkyl ester as a plasticizer, or (c2) about 5 wt % to about 25 wt % of at least one kind of a second tackifier resin, having a DACP of less than 0 C. and an MMAP of less than +30 C., and (d2) about 5 wt % to about 15 wt % of at least one kind of an aliphatic or cycloaliphatic alkyl ester as a plasticizer.

2. Adhesive composition according to claim 1, wherein the vinylaromatic block copolymer is a styrene block copolymer.

3. Adhesive composition according to claim 1, wherein the second tackifier resin is a rosin, a crude tall oil resin, a hydrogenated resin ester or a disproportionated rosin ester.

4. Adhesive composition according to claim 1, wherein the plasticizer is at least one plasticizer selected from the group consisting of esters of aliphatic or cycloaliphatic carboxylic acids, esters of dicarboxylic acids, and phosphoric esters.

5. Adhesive composition according to claim 4, wherein the plasticizer is at least one plasticizer selected from the group consisting of alkyl or cycloalkyl adipates, di(2-ethylhexyl) adipate, diisononyl adipate, diisodecyl adipate, ditridecyl adipate and dioctyl adipate, alkyl or cycloalkyl sebacates, di(2-ethylhexyl) sebacate, and alkyl or cycloalkyl azelates, di(2-ethylhexyl) azelate, aliphatic or cycloaliphatic cyclohexyldicarboxylic diesters, 1,2-diisobutylcyclohexanedicarboxylic esters, 1,2-di-(2-ethylhexyl)cyclohexanedicarboxylic esters or 1,2-diisononylcyclohexanedicarboxylic esters.

6. Adhesive composition according to claim 5, wherein the plasticizer is an aliphatic or cycloaliphatic cyclohexyldicarboxylic diester, a 1,2-diisobutylcyclohexanedicarboxylic ester, a 1,2-di-(2-ethylhexyl)cyclohexane dicarboxylic ester or a 1,2-diisononylcyclohexanedicarboxylic ester.

7. Adhesive composition according to claim 1, further comprising at least one UV protectant.

8. Adhesive composition according to claim 1, further comprising at least one antioxidant or an ageing inhibitor selected from the group of the mono- and/or polynuclear phenols carrying a benzyl thioether moiety positioned ortho and/or para to the phenolic OH group.

9. Adhesive composition according to claim 2, wherein the vinylaromatic block copolymer is an at least one saturated styrene block copolymer taking the form of a diblock copolymer with a proportion in relation to the elastomer components of up to about 50 wt %.

10. Adhesive tape comprising at least one adhesive composition according to claim 1.

11. Adhesive tape according to claim 10, further comprising a carrier.

12. Adhesive tape according to claim 10, wherein the adhesive tape is a transfer tape.

13. Method of using adhesive tape according to claim 10 for bonding on a porous and/or rough substrate.

14. Adhesive composition according to claim 1, wherein the at least one kind of the saturated vinylaromatic block copolymer is present at about 30 wt % to about 40 wt %.

15. Adhesive composition according to claim 1, wherein the at least one kind of the first tackifier resin is present at about 25 wt % to about 45 wt %.

16. Adhesive composition according to claim 1, wherein the at least one kind of the second tackifier resin is present at about 10 wt % to about 20 wt %.

17. Adhesive composition according to claim 2, wherein the styrene block copolymer comprises a polystyrene-poly(ethylene-co-butylene) block copolymer (SEBS), a polystyrene-poly(ethylene-co-propylene) block copolymer (SEPS), a polystyrene-poly(isoprene-co-butadiene) block copolymer saturated in an elastomer block (SEEPS), a polystyrene-polyisobutylene block copolymer (SiBS), or a mixture thereof.

18. Adhesive composition according to claim 7, wherein the at least one UV protectant is present in an amount of about 0.5 wt % to about 2 wt %.

19. Adhesive composition according to claim 8, wherein the at least one antioxidant is present in an amount of about 0.2 wt % to about 1.5 wt %.

20. Adhesive composition according to claim 9, wherein the diblock copolymer is present with a proportion in relation to the elastomer components of about 10 wt % to about 30 wt %.

Description

EXAMPLES

Preparation of Specimens

[0115] The adhesive compositions were produced in a heatable double-sigma III-P1 hotmelt compounder from Aachener Maschinenbau Kupper. The jacket of the compounder was heated by means of a thermal oil heating bath from Lauda. The bath temperature set in this case was 190 C. Throughout the kneading operation, there was a protective gas atmosphere of CO.sub.2. The compounder was operated at 50 rpm.

[0116] First of all the elastomers, together with the solid ageing inhibitor Irganox 1076 and also two UV protectants (a benzotriazole derivative and a HALS derivative), were weighed out and introduced into the compounder. Thereafter about 10% of the amount of solid resin was added (as far as possible according to the formula, resin I is chosen for this purpose) and kneading took place for 15 minutes. After that, at intervals of 10 minutes each, portions of one-third of the remaining quantity of tackifier resins, and also, lastly, plasticizer were added and incorporated.

[0117] After the end of the kneading operation, the kneading compounds were taken from the compounder and allowed to cool to room temperature.

[0118] The cooled compositions were positioned between two plies of siliconized release paper and pressed with a RLKV 25 hot press from Lauffer GmbH & CO KG at 130 C. to form hand specimens with the respective layer thickness. The adhesive layers were laminated onto a carrier material. This was done manually using a rubber roller. The carrier material employed was a cast polypropylene film 90 m thick.

Base Materials Used

[0119]

TABLE-US-00002 TABLE 1 base materials used Name Type Manufacturer Elastomer Kraton G1657 *) Polystyrene-poly(ethylene-co- Kraton Polymers butylene) block copolymer, SEBS (polystyrene fraction 13 wt %; diblock fraction 29 wt %) Tackifier resin I Regalite R1125 Hydrocarbon resin (MMAP 83 C.; Eastman Chemical DACP 55 C., TRB 123 C.) Tackifier resin II Foral AX-E Rosin ester (MMAP 21 C.; Eastman Chemical DACP <50 C., TRB 75 C.) Foral 105-E Rosin ester (MMAP 16 C.; Eastman Chemical DACP <50 C., TRB 101 C.) Foral 85-E Rosin ester (MMAP 7 C.; Eastman Chemical DACP <50 C., TRB 80 C.) Plasticizers Hexamoll Dinch Cyclohexyldicarboxylic diester BASF SE Wingtack 10 C5 plasticizer resin Cray Valley Indopol H100 Polybutene Ineos Europe Abitol E Hydroabietyl alcohol Eastman Chemical Dercolyte LTG Polyterpene plasticizer resin DRT Ageing inhibitor Irganox 1076 Sterically hindered phenol BASF SE UV protectants A Benzotriazole derivative B HALS derivative *) cf. product information for Kraton Product Guide Innovation Powered by Kraton Polymers from 2016.

Examples

[0120] All figures in wt %; all of the adhesive compositions (100 parts) also contained an additional 0.5 part each of a benzotriazole derivative, of a HALS derivative and of Irganox 1076.

TABLE-US-00003 TABLE 2 Example Example Example Example Example Example Base materials I1 I2 I3 I4 I5 I6 Elastomer Kraton 1657 38.0 35.0 40.0 30.0 35.0 30.0 Tackifier resin I Regalite R1125 42.0 40.0 20.0 40.0 40.0 36.0 Tackifier resin II Foral AX-E 5.0 25.0 15.0 12.5 20.0 Plasticizer Hexamoll Dinch 20.0 20.0 15.0 15.0 12.5 14.0 Layer thickness [m] 160 160 160 160 120 160 Bond strength 8.0 12.5 12.6 13.2 8.7 13.0 (Test V) [N/cm] Detachment Fibre Fibre Fibre Fibre Fibre Fibre behaviour (Test V) extraction extraction extraction extraction extraction extraction Ageing OK OK OK OK OK OK resistance (Test VI)

TABLE-US-00004 TABLE 3 Base Example Example Example Example Example materials C1 C2 C3 C4 C5 Elastomer 38.0 38.0 38.0 38.0 38.0 Kraton 1657 Tackifier 42.0 42.0 42.0 42.0 42.0 resin I Regalite R1125 Tackifier 20.0 resin II Foral AX-E Plasticizers 20.0 20.0 20.0 20.0 Wingtack 10 Indopol H100 Abitol-E Dercolyte LTG Layer 160 160 160 160 120 thickness [m] Bond 4.4 0.8 1.6 1.2 1.0 strength (Test V) [N/cm] Detachment Adhesive Adhesive Adhesive Adhesive Adhesive behaviour (Test V) Ageing Not Not Not Not Not resistance carried carried carried carried carried (Test VI) out out out out out

TABLE-US-00005 TABLE 4 Example Example Example Example Example Example Base materials I7 I8 I9 I10 C6 C7 Elastomer Kraton 1657 30.0 30.0 30.0 30.0 30.0 30.0 Tackifier resin I Regalite R1125 40.0 40.0 40.0 30.0 35.0 39.0 Tackifier resin II Foral AX-E 15.0 25.0 15.0 13.0 Foral 105-E 15.0 Foral 85-E 15.0 Plasticizer Hexamoll Dinch 15.0 15.0 15.0 15.0 20.0 18.0 Layer thickness [m] 120 120 120 160 160 160 Bond strength 11.9 9.2 14.1 9.0 3.6 7.7 (Test V) [N/cm] Detachment Fibre Fibre Fibre Fibre Cohesive Cohesive behaviour (Test V) extraction extraction extraction extraction Ageing OK OK OK OK Not Not resistance (Test VI) carried out carried out

[0121] Table 2 shows various adhesive compositions of the invention along with their properties in respect of bond strength, detachment behaviour and ageing resistance. The proportions of elastomer, tackifier resin I and optionally II, and plasticizer are varied within the ranges according to the invention. The adhesive compositions of the invention have a bond strength of at least 8.0 N/cm, and during the detachment operation there is the (desired) fibre extraction from the web material. Furthermore, all of the adhesive compositions of the invention passed the ageing resistance test to complete satisfaction.

[0122] In the case of the comparative examples which are reproduced in Table 3, either no plasticizer (Example C1) or no plasticizer in accordance with the invention (Examples C2 to C5) is used. Besides only low bond strengths, the adhesive compositions part adhesively from the web material, meaning that anchorage on the web material is inadequate, and adhesive composition and web material become separated from one another in the course of the detachment operation.

[0123] Table 4 embraces inventive examples 17 to 110 and also non-inventive, comparative examples C6 and C7. The latter contain a quantity of plasticizer that is too great for the proportion of tackifier resin II. The consequence is an excessively elastic adhesive composition which exhibits cohesive detachment of the adhesive composition; i.e., the anchorage on the web is indeed present, but there is detachment within the adhesive layer at low bond strengths of below 8 N/cm.

[0124] After corresponding testing for the ageing resistance, all of the adhesive compositions of the invention show a visually appealing appearance without deformations or other impairments.

[0125] With the present invention, accordingly, success has been achieved in providing adhesive compositions which are suitable for bonding on porous and/or fibrous materials and at the same time have a high long-term stability.