Hot-melt adhesive in particulate form

• US 20040143034A1
• Filed: 11/07/2003
• Published: 07/22/2004
• Est. Priority Date: 05/09/2001
• Status: Active Grant

• Current Assignee: Henkel KGaA (Henkel AG & Co KGaA)
• Original Assignee: Henkel KGaA (Henkel AG & Co KGaA)
• Inventors: Nixon, Andrew, Rudolph, Michael, Krebs, Michael, Kohlstadt, Hans-Peter, Primke, Hartmut, Scheffler, Ingolf, Wichelhaus, Juergen, Petry, Gerald
• Granted Patent: US 7,267,878 B2
• Time in Patent Office: Days
• US Class Current: 523/176
• CPC Class Codes: B29B 9/10 by moulding the material, i.e. treating it in the molten state
• CPC Class Codes: B29K 2105/0097 Glues or adhesives, e.g. hot melts or thermofusible adhesives
• CPC Class Codes: C08G 18/12 using two or more compounds having active hydrogen in the first polymerisation step
• CPC Class Codes: C08G 18/307 Atmospheric humidity
• CPC Class Codes: C08G 18/4018 Mixtures of compounds of group C08G18/42 with compounds of group C08G18/48
• CPC Class Codes: C08G 2170/20 Compositions for hot melt adhesives
• CPC Class Codes: C08J 2367/02 Polyesters derived from dicarboxylic acids and dihydroxy compounds; C08J2367/06 takes precedence
• CPC Class Codes: C08J 3/12 Powdering or granulating
• CPC Class Codes: C08L 29/00 Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal or ketal radical; Compositions of hydrolysed polymers of esters of unsaturated alcohols with saturated carboxylic acids; Compositions of derivatives of such polymers
• CPC Class Codes: C09J 175/04 Polyurethanes
• CPC Class Codes: C09J 201/02 characterised by the presence of specified groups , e.g. terminal or pendant functional groups
• CPC Class Codes: C09J 5/06 involving heating of the applied adhesive
• CPC Class Codes: Y10T 428/31551 Of polyamidoester [polyurethane, polyisocyanate, polycarbamate, etc.]
• CPC Class Codes: Y10T 428/31562 Next to polyamide [nylon, etc.]
• CPC Class Codes: Y10T 428/31565 Next to polyester [polyethylene terephthalate, etc.]
• CPC Class Codes: Y10T 428/3158 Halide monomer type [polyvinyl chloride, etc.]

Abstract

A moisture-curing hot-melt-adhesive composition in granulate, tablet or powder form can be produced by

a.) fusing the reactive hot-melt-adhesive composition and heating the melt, subject to exclusion of moisture,

b.) extruding this melt through one or more dies onto a cooled surface, subject to exclusion of moisture,

c.) cooling the granulate, subject to exclusion of moisture, whereby the composition solidifies,

d.) removing the cooled hot-melt-adhesive granulate,

e.) filling the granulate into moisture-tight packages, subject to exclusion of moisture.

These reactive hot-melt adhesives are pourable and free-flowing and therefore can be used with all conventional application machines for hot-melt adhesives.

Claims

1. A one part hot-melt adhesive composition in the form of particles and comprised of polymeric constituents, wherein at least some of the polymeric constituents contain moisture-reactive groups and wherein said particles have surfaces which are not tacky at temperatures below 35 degrees C.

2. The one part hot-melt-adhesive of claim 1, wherein said particles are in the form of a granulate.

3. The one part hot-melt adhesive composition of claim 1, wherein the moisture-reactive groups are selected from the group consisting of isocyanate groups, silanol groups, alkoxysilane groups, acetoxysilane groups, silazane groups, oximatosilane groups and mixtures thereof.

4. The one part hot-melt adhesive composition of claim 1, additionally comprising at least one material selected from the group consisting of radiation-curable polymers and monomers.

5. The one part hot-melt adhesive composition of claim 4, wherein the at least one material contains groups selected from the group consisting of olefinically unsaturated groups, epoxide groups and combinations thereof.

6. The one part hot-melt adhesive composition of claim 1, wherein the particles have a particle size of from 0.5 mm to 30 mm.

7. The one part hot-melt adhesive composition of claim 1, wherein the particles have a particle size from 5 microns to 500 microns.

8. The one part hot-melt adhesive composition of claim 1, wherein said composition when melted has a viscosity at 150±

20°

C. of 10±

5 Pa.s.

9. A process for producing the one part hot-melt adhesive of claim 1, comprising the following steps:

a) heating the polymeric constituents to a temperature between 110 degrees C. and 180 degrees C. to form a melt, subject to exclusion of moisture;

b) extruding the melt through one or more dies with a diameter from 0.5 mm to 30 mm onto a cooled surface, subject to exclusion of moisture;

c) cooling the extruded melt, subject to exclusion of moisture, whereby the extruded melt solidifies to form the one part hot-melt adhesive composition in the form of particles;

d) removing the particles from the cooled surface;

e) filling the particles into a moisture-tight package, subject to exclusion of moisture.

10. The process according to claim 9, wherein the extruded melt is treated after step b) with one or more tackiness-reducing agents.

11. The process according to claim 10, wherein the tackiness-reducing agents are selected from the group consisting of fine-particle dusts in the form of carbon black, highly dispersed silicic acid, polyethylene powder or talc and low-melting waxes and paraffins that are capable of being sprayed on or sputtered on in solid form.

12. The process according to claim 9, wherein said particles are subjected to post-crystallizing in an agitated, temperature-controlled, moisture-proof receptacle.

13. The process according to claim 9, wherein the melt is extruded through one or more dies under pressure in a pulsed manner so that individual drops of the melt are formed.

14. A process for bonding planar objects or moldings, comprising the following steps:

a.) homogenizing and fusing the one part hot-melt adhesive composition according to claim 1, subject to exclusion of moisture and/or oxygen, by using a heatable mixing unit;

b.) applying a layer of the homogenized and fused one part hot-melt adhesive composition onto at least one surface of a first sheet material or molding;

c.) joining a second sheet material or molding onto said layer to form a composite system; and

d.) cooling the composite system to room temperature, whereby the one part hot-melt adhesive composition solidifies and cures, subject to crosslinking.

15. The process according to claim 14, wherein the homogenized and fused one part hot-melt adhesive composition in step b) is applied with the aid of an applicator roll or a doctor blade or by spray application.

16. The process according to claim 14, wherein prior to the joining in accordance with step c) the layer of homogenized and fused one part hot-melt adhesive composition is exposed to electromagnetic radiation in the form of UV, electron or NIR radiation.

17. The process according to claim 16, wherein at least one of the first sheet material or molding or the second sheet material or molding is transparent to the electromagnetic radiation and the layer is exposed to the electromagnetic radiation after the joining in accordance with step c).

18. The process according to claim 14, wherein after step c) and before step d) mechanical fixing of the first sheet material or molding and the second sheet material or molding is performed.

19. The process according to claim 14, wherein the homogenized and fused one part hot-melt adhesive composition is extruded through a shaping die when applied in step b).

20. A composite system comprising a first sheet material or molding, a second sheet material or molding, and a solidified, cured layer of the one part hot-melt adhesive composition of claim 1 joining said first sheet material or molding and said second sheet material or molding.

21. The composite system according to claim 20, wherein said composite system is selected from the group consisting of wood parts, furniture parts, window profiles, solar collectors, filters, vehicle parts, books, textiles, composite foils, shoes, sports equipment, structural facade units, casting resin panes, and laminated insulating glasses.