HOT MELT ADHESIVE WITH NON-HYDROGENATED HIGH SOFTENING POINT C5 TACKIFYING AGENT

Abstract

The invention includes a hot melt adhesive composition including a single-site catalyzed propylene-based polymer that has a co-monomer content of from 0% by weight to 20% by weight and a Brookfield Viscosity at 190 C. of no greater than 25,000; and a non-hydrogenated C5 tackifying agent having a softening point of from 98 C. to around 130 C. The adhesive composition has been found to give a good balance of static peel strength and dynamic peel strength when used as a construction adhesive in a disposable absorbent article.

Claims

1. A hot melt adhesive composition comprising: a.) a single-site catalyzed propylene-based polymer that has a co-monomer content of from 0% by weight to 20% by weight and a Brookfield Viscosity at 190 C. of no greater than 25,000; and b.) a non-hydrogenated high softening point C5 tackifying agent having a softening point of from 98 C. to around 130 C.

2. The hot melt adhesive composition of claim 1 further comprising c.) From 5% to 35% by weight of a plasticizer.

3. The hot melt adhesive composition of claim 2 further comprising d.) a second tackifying agent.

4. The hot melt adhesive composition of claim 3 wherein the second tackifying agent is at least partially hydrogenated.

5. The hot melt adhesive of claim 1 wherein the non-hydrogenated high softening point C5 tackifying agent is derived from at least 50% by weight C5 monomers.

6. The hot melt adhesive of claim 1 wherein the non-hydrogenated high softening point C5 tackifying agent is derived from at least 75% by weight C5 monomers.

7. The hot melt adhesive composition of claim 1 comprising 15% by weight to 55% by weight of the non-hydrogenated high softening point C5 tackifying agent.

8. The hot melt adhesive composition of claim 1 comprising 15% by weight to 70% by weight of the single-site catalyzed propylene-based polymer.

9. The hot melt adhesive composition of claim 1 wherein the non-hydrogenated high softening point C5 tackifying agent has a Molten Gardner Color (50% by weight in toluene) of no greater than 6.

10. The hot melt adhesive composition claim 1 wherein the single-site catalyzed propylene-based polymer comprises a single-site catalyzed propylene-based homopolymer and a single-site catalyzed propylene-based copolymer.

11. The hot melt adhesive composition of claim 1 further comprising a wax.

12. The hot melt adhesive composition of claim 2 comprising 5% by weight to 20% by weight of a naphthenic oil plasticizer.

13. The hot melt adhesive composition of claim 2 comprising a naphthenic oil plasticizer and from 15% by weight to 55% by weight of the non-hydrogenated high softening point C5 tackifying agent.

14. The hot melt adhesive composition of claim 3, where the sum of a.), b.), and c.) and d.) makes up at least 90% of the composition.

15. The hot melt adhesive composition of claim 1 having a Brookfield Viscosity at 150 C. of no greater than 16,000 cP.

16. A disposable absorbent article comprising: a.) a body fluid impermeable back sheet, b.) a nonwoven top sheet, and c.) a hot melt adhesive composition comprising: i. a single-site catalyzed propylene-based polymer that has a co-monomer content of from 0% by weight to 20% by weight and a Brookfield Viscosity at 190 C. of no greater than 25,000; and ii. a non-hydrogenated high softening point C5 tackifying agent having a softening point of from 98 C. to around 130 C. wherein the body fluid impermeable back sheet is adhered to the nonwoven top sheet through the hot melt adhesive composition.

17. The disposable absorbent article of claim 16 wherein the hot melt adhesive composition comprises from 15% by weight to 55% by weight of the non-hydrogenated high softening point C5 tackifying agent.

18. The disposable absorbent article of claim 16 wherein the single-site catalyzed propylene-based polymer comprises a single-site catalyzed propylene-based homopolymer and a single-site catalyzed propylene-based copolymer.

Description

EXAMPLES

Test Procedures

[0066] Test procedures used in the examples and throughout the specification, unless stated otherwise, include the following.

Adhesive Sample Preparation

[0067] The hot melt adhesive samples were prepared in a sigma blade mixer with a batch size of 5000 grams. A heating oil temperature of around 177 C. was used. The polymer, tackifying agent and additives were added first, blended until smooth and then the plasticizer was added in portions. The mixture was allowed to mix until homogeneous and then dumped. Each sample took about 1 hour to make.

Viscosity Test Method

[0068] Viscosity is determined in accordance with ASTM D-3236 entitled, Standard Test Method for Apparent viscosity of Adhesives and Coating Materials, (Oct. 31, 1988), using a Brookfield Thermosel viscometer Model RVDV 2 and a number 27 spindle. The results are reported in centipoise (cP).

Mettler Dropping Point

[0069] ASTM D 6090, with a heating rate of 2 C./min.

Peel Test Sample Preparation

[0070] A Summit spray applicator and laminator were set to an application temperature of 150 C., a nip pressure of 41.4 kilopascal (6 psi), an application weight as shown in the tables, and minimal rewind and unwind tensions so as not to stretch film. The continuous slot pattern is 1 inch (25.4 mm wide) wide. The back sheet was passed through the applicator and then the top sheet nonwoven was nipped into place.

[0071] The Top Sheet Nonwoven was UNIPRO 45 a nonwoven web from Midwest Filtration Company). The Back Sheet was Breathable film PW100429 BR149 16 GSM, 58.8 wide 7500 WVTR Large OD) available from Clopay Plastic Products Company, Inc., (Cincinnati, Ohio).

[0072] The speed at which the film passes through the applicator is from 213.4 meters per minute (700 feet per minute (ft/min)) to 274.3 meters per minute (900 ft/min). A sufficient amount of laminate is prepared such that 152.4 centimeters (60 inches) of representative lamination can be collected for testing.

Static Peel Test Method

[0073] From the laminations made in the sample preparation above, 4 inch wide (102 mm) test samples are cut. The samples are hung in an oven at 38C (100F) in a peel mode. 25 g of weight is placed on the sample. Samples are peeled in the cross-machine direction. The time to failure is measured in minutes. Six replicates are tested and the average time to fail is listed in the table.

Dynamic Peel Test Method

[0074] The Dynamic Peel test is used to measure the bond strength of an adhesive coated between two flexible substrates. Dynamic Peel is determined using ASTM D1876-01 entitled, Test Method for Determining Peel Resistance of Adhesive (T-Peel Test Method), with the exception that it is run at 30.5 centimeters per minute (12 inches per minute), instead of 25.4 centimeters per minute (10 inches per minute), over a period of 10 seconds, and 7 replicates are run instead of the 10 specified in ASTM D1876. The samples are run on an INSTRON type test instrument. Unless otherwise specified, the test samples are prepared as described in the Sample Preparation test method. The samples are peeled in the machine direction. The average peel value over 10 seconds of peeling is recorded, and the results are reported in grams. The initial

[0075] Dynamic Peel value is the value measured 24 hours after the laminate is prepared.

TABLE-US-00001 TABLE 1 HAITACK QUINTONE QUINTONE PICCOTAC JH-3200 A100 RX110 1115 Ring and Ball 89-96 100 110 110 Softening Point ASTM E-28 ( C.) Mettler 91.7 99 109 116 Dropping Point ( C.) Gardner Color 3.3 4 2 3

TABLE-US-00002 TABLE 2 C1 Ex 1 Ex 2 Ex3 HAITACK JH-3200 39.4 QUINTONE A100 39.4 QUINTONE RX110 39.4 PICCOTAC 1115 39.4 Brookfield Viscosity @ 149 C. 4075 4375 5012 4800 (300 F.) - cP Substrates: BS/TSNW Static Peel (@39 C.) 15.3 22.2 26.7 26.8 (coat weight = 5 gsm) - minutes Static Peel (@39 C.) 17.3 28.7 32.2 30 (coat weight = 6 gsm) - minutes Dynamic Peel @ 23 C. (initial, 495 504 552 517 coat weight = 5 gsm) Dynamic Peel @ 23 C. (2 wks 567 593 612 577 aged, coat weight = 5 gsm)

[0076] Compositions C1, Ex 1, Ex 2 and Ex 3 are all the same composition with the exception of the tackifying agent which is as listed in Table 2. In addition to the tackifying agent all compositions include 29% by weight single-site catalyzed propylene-based polymer, 24% plasticizer, 5% wax and 2.4% additional components.

TABLE-US-00003 TABLE 3 Ex 4 Ex 5 LMODU S400 10 VISTAMAXX 8380 50 40 PICCOTAC 1115 39.75 39.75 CALSOL 5550 10 10 BNX 1076 0.25 0.25 Viscosity @ 149 C. 3870 5125 (300 F.) - cP Substrates: BS/TSNW Static Peel (@39 C.) (coat 14.3 34 weight = 5 gsm) - minutes Dynamic Peel @ 23 C. 243 272 (initial, coat weight = 5 gsm) Dynamic Peel @ 23 C. Not tested Not tested (2 wks aged, coat weight = 5 gsm)

Table 3Substrates

[0077] The substrates were the same with the exception that the back sheet use was D11-284 PE MICROFLEX Embossed Non-Breathable film available from Clopay Plastic Products Company, Inc., (Cincinnati, Ohio))
Comment: In Table 2 (versus Table 3) a lower basis weight film (which is easier to bond to) was used as a back sheet. This gave the examples in Table 2 somewhat higher peel values (versus those in Table 3).

[0078] Other embodiments are within the claims.