Hot melt adhesive

Abstract

A hot melt adhesive material and articles made using the hot melt adhesive to assemble structures in an article. The adhesive material typically is manufactured by blending amorphous polymer with a compatible amorphous polymer.

Claims

1. A hot melt adhesive composition comprising: (i) from about 50 wt. % to about 90 wt. % of an amorphous polyolefin copolymer comprising more than 40 mole % 1-butene, the amorphous polyolefin copolymer having a viscosity of between 2000 and 8000 cps at a temperature of about 190 C.; and (ii) from about 10 wt. % to about 50 wt. % of a second amorphous polymer comprising at least one butene monomer, the second amorphous polymer having a molecular weight (MW.sub.n) of at least 1000, wherein the second amorphous polymer is compatible with the amorphous polyolefin copolymer.

2. The hot melt adhesive composition of claim 1, wherein the adhesive is substantially free of a tackifier.

3. The hot melt adhesive composition of claim 1, wherein the second amorphous polymer comprises a viscous liquid with molecular weight of about 1,000-20,000 and a Saybolt Universal seconds (SUS) viscosity at 100 C. of about 100 to 20,000.

4. The hot melt adhesive composition of claim 1, wherein the second amorphous polymer comprises a polyisobutylene with a molecular weight of 1,500 to 6,000.

5. The hot melt adhesive composition of claim 1, wherein the density of the adhesive composition is less than 0.9 g-cm.sup.3.

6. The hot melt adhesive composition of claim 1, wherein the density of the adhesive composition is less than 0.87 g-cm.sup.3.

7. A disposable article comprising a substrate combined with a film, fiber, cellulose sheet or non-woven having an adhesive bond there between comprising the adhesive of claim 1.

8. A disposable diaper article comprising a substrate combined with a film, fiber, cellulose sheet or non-woven having an adhesive bond there between comprising the adhesive of claim 1.

9. The hot melt adhesive composition of claim 1, wherein the adhesive is substantially free of a tackifier.

10. The hot melt adhesive composition of claim 1, wherein the second amorphous polymer comprises a viscous liquid with molecular weight of about 1,000-20,000 and a Saybolt Universal seconds (SUS) viscosity at 100 C. of about 100 to 20,000.

11. The hot melt adhesive composition of claim 1, wherein the second amorphous polymer comprises a polyisobutylene with a molecular weight of 1,500 to 6,000.

12. The hot melt adhesive composition of claim 1, wherein the density of the adhesive is less than 0.9 g-cm.sup.3.

13. The hot melt adhesive composition of claim 1, wherein the density of the adhesive is less than 0.87 g-cm.sup.3.

14. A hot melt adhesive composition comprising: (i) about 90 wt. % to about 10 wt. % of an amorphous polyolefin composition comprising a copolymer having more than 40 mole % 1-butene, the copolymer having a viscosity of between 2000 and 8000 cps at a temperature of 190 C.; and (ii) about 0.1 wt. % to about 50 wt. % of a polyisobutylene; wherein the adhesive composition is substantially free of a tackifier; wherein the hot melt adhesive composition has a softening point temperature range of 115 C. to about 130 C.

15. The hot melt adhesive composition of claim 14, wherein the polyisobutylene has a molecular weight of about 2000 to 3000.

16. The hot melt adhesive composition of claim 14, wherein the density of the adhesive composition is less than 0.9 g-cm.sup.3.

17. The hot melt adhesive composition of claim 14, wherein the density of the adhesive composition is less than 0.87 g-cm.sup.3.

18. A disposable article comprising a substrate combined with a film, fiber, cellulose sheet or non-woven having an adhesive bond there between comprising the adhesive of claim 14.

19. A disposable diaper article comprising a substrate combined with a film, fiber, cellulose sheet or non-woven having an adhesive bond there between comprising the adhesive of claim 14.

20. A hot melt adhesive composition consisting essentially of: (i) a blend of amorphous polyolefin copolymers, each amorphous polyolefin copolymer comprising more than 40 mole % 1-butene, at least one amorphous polyolefin copolymer having a viscosity of between 2000 and 8000 cps at a temperature of 190 C.; and (ii) a second amorphous polymer comprising at least one butene monomer, the polymer having a molecular weight (MW) of at least 1000 wherein the polymer is compatible with the polyolefin.

21. A disposable article comprising a substrate combined with a film, fiber, cellulose sheet or non-woven having an adhesive bond there between comprising the adhesive of claim 20.

22. A disposable diaper article comprising a substrate combined with a film, fiber, cellulose sheet or non-woven having an adhesive bond there between comprising the adhesive of claim 20.

23. A hot melt adhesive composition consisting essentially of: (i) an amorphous polyolefin copolymer comprising more than 40 mole % 1-butene, the amorphous polyolefin copolymer having a viscosity of between 2000 and 8000 cps at a temperature of 190 C.; and (ii) a second amorphous polymer comprising at least one butene monomer, the second amorphous polymer having a molecular weight (MW.sub.n) range of about 5,000 to about 45,000, wherein the second amorphous polymer is compatible with the amorphous polyolefin copolymer; wherein the hot melt adhesive composition has a softening point temperature range of 115 C. to about 130.

Description

EXPERIMENTAL

(1) A number of hot melt adhesive compositions were prepared by blending first amorphous copolymer, second compatible copolymer and antioxidant under mixing conditions at elevated temperatures to form a fully homogenized melt. Mixing temperatures varied from about 135 to about 200 C. preferably about 150 to about 175 C. as needed to obtain uniformity. A traditional heated stirred blade (WiseStir) mixer was used to ensure full homogenization in a heated container into a final adhesive composition.

Examples 1-3

(2) Hot melt adhesive compositions were formulated by melt blending, as described below, wherein specific components and amounts of the components are shown in the following table 2.

(3) TABLE-US-00002 TABLE 2 Experimental Preparations Ex. 1 Ex. 2 Ex. 3 Component (wt. %) (wt. %) (wt. %) Rextac E-65 44.5 54.5 (1-butene copolymer) Rextac E-63 30 20 (1-butene copolymer) Rextac 2830 70 (1-butene copolymer) Indapol H-1900 24.99 24.99 29.49 Polyisobutylene (MW2500) Irganox 1010 (Stabilizer) 0.5 0.5 0.5 Benotex OB 0.01 0.01 0.01 (Optical brightener) Brookfield DV-II + pro Viscosity (cP) Rotation 10 rpm Spindle # SC4-27 250 F. 31000 23825 18200 275 F. 13650 13175 10250 300 F. 6265 6875 6050 325 F. 4090 4460 3850 350 F. 3245 3060 2595 Mettler Softening 116 115 91 Point ( C.) Density (g-cm.sup.3) 0.87 0.87 0.87

Comparative Example 1

(4) Hot melt adhesive compositions is formulated by melt blending, as described below, wherein specific components and amounts of the components are shown in the following table 3.

(5) TABLE-US-00003 TABLE 3 Experimental Preparations CEx. 1 CEx. 2 Component (wt. %) (wt. %) APAO 75 Rextac E-63 75 (1-butene copolymer) Polyisobutylene 25 White Oil 25 Irganox 1010 (Stabilizer) 0 0 Benotex OB 0 0 (Optical brightener)
Comparative examples 1 and 2 forms a non-uniform composition that has insufficient cohesive/adhesive strength to be usefully measured.

(6) TABLE-US-00004 TABLE 4 Test Results Add-on Add-on method - (g-m.sup.2) Nordsen Over Air Press. Web Speed Peak Average Hot Melt 120 mm Temp (psi/ (inch-sec.sup.1/ Peel Peel Peel force Run applic. width ( F./ C.) Gap Pascal) m-sec.sup.1) Ex. Ex. Ex. (g-in.sup.1) (g-in.sup.1) (N-cm.sup.1) 1 Slot/true 0.75 320/160 2000/50.8 Ex. 2 190 93 0.37 coat die 2 Slot/true 1 310/154.4 2000/50.8 Ex. 2 202 110 0.43 coat die 3 Slot/true 1 320/160 2000/50.8 Ex. 2 217 134 0.53 coat die 4 Slot/true 1 330/165.6 2000/50.8 Ex. 2 212 131 0.52 coat die 5 Slot/true 1 315/157.2 2000/50.8 Ex. 2 205 110 0.43 coat die 6 Slot/true 0.5 320/160 2000/50.8 Ex. 2 111 58 0.23 coat die 7 Slot/true 0.75 320/160 2000/50.8 Ex. 2 161 95 0.37 coat die 8 Slot/true 0.5 320/160 2000/50.8 Ex. 1 126 70 0.28 coat die 9 Slot/true 0.75 320/160 2000/50.8 Ex. 1 181 100 0.39 coat die 10 Slot/true 0.5 320/160 2000/50.8 Ex. 3 117 62 0.24 coat die 11 Slot/true 0.75 320/160 2000/50.8 Ex. 3 152 93 0.37 coat die 12 Slot/true 1 320/160 2000/50.8 Ex. 3 192 123 0.48 coat die 13 Signature 1 360/182.2 20 mm 40/0.276 2000/50.8 Ex. 2 154 92 0.36 14 Signature 1 360/182.2 20 mm 45/0.310 2000/50.8 Ex. 2 164 96 0.38 15 Signature 1 360/182.2 25 mm 45/0.310 2000/50.8 Ex. 2 189 102 0.4 16 Signature 1.25 360/182.2 25 mm 45/0.310 2000/50.8 Ex. 2 201 123 0.48 17 Signature 1.25 360/182.2 25 mm 45/0.310 2000/50.8 Ex. 3 187 116 0.46 18 Signature 1 360/182.2 25 mm 45/0.310 2000/50.8 Ex. 3 158 88 0.35 19 Signature 1 360/182.2 25 mm 45/0.310 2000/50.8 Ex. 1 197 122 0.48 20 Signature 1.25 360/182.2 25 mm 45/0.310 2000/50.8 Ex. 1 232 138 0.54

(7) All tests show adhesion and good bonding. The data from runs 2, 3, 4, 5, 9, 12, 15, 16, 17, 19 and 20 show values that all exceeded requirements for a successful construction manufacture.

(8) These data indicates that the materials will provide excellent construction bonding in disposable absorbent articles. Note viscosity relates to the resistance to flow of the material under certain conditions. This distinctive property determines the flowability, degree of wetting, and penetration of the substrate by the molten polymer. It provides an indication of its processability and utility as a hot melt adhesive material.

(9) Melt viscosity is generally directly related to a polymer molecular weight and is reported in millipascal-second (mP.Math.s) or centipoise (cP) using a Brookfield DV-II+Pro (Rotation 10 rpmSpindle # SC4-27) at the stated temperature

(10) Mettler softening point in degrees Centigrade or degrees Fahrenheit is typically measured using ASTM D3104. The amorphous nature of the poly olefin materials results in a melting point, which is not sharp or definite. Rather as the temperature increases, amorphous polymers gradually change from a solid to a soft and then to a liquid material. No clearly defined glass transition or melting temperature is often noted. This temperature testament that generally measures the precise temperature at which a disc of polymer sample, heated at a rate of 2 C. per minute or 10 F. per minute becomes soft enough to allow the test object, a steel ball (grams) drops through the sample. The softening point of a polymer reported in degrees Centigrade or degrees Fahrenheit is important because it typically indicates the polymer's heat resistance, useful application temperatures and solidification points.

(11) Peel test values were obtained by forming a laminate from a SMS non-woven (11.6 g-m.sup.2) micro-porous polyethylene film (0.5 mil/0.127 micron) using lamination conditions as shown in Table 4. The laminate is cut into 1 inch/25.4 mm wide strips in the cross machine direction. Peel force was measured by separating the laminate at room temperature using a TMax pull tester at a rate of 20 in-sec.sup.1/50.8 cm-sec.sup.1 with the peek force averaged over a 15 period.

(12) The claims may suitably comprise, consist of, or consist essentially of, or be substantially free of any of the disclosed or recited elements. The invention illustratively disclosed herein can also be suitably practiced in the absence of any element which is not specifically disclosed herein. The various embodiments described above are provided by way of illustration only and should not be construed to limit the claims attached hereto. Various modifications and changes may be made without following the example embodiments and applications illustrated and described herein, and without departing from the true spirit and scope of the following claims.