RADIATION CURABLE PRIMER ADHESIVE

Abstract

The present invention involves a 100% solids, radiation curable adhesive formulation for adhesion to EVA. This formulation may have varying compositions, as discussed in detail herein. However primarily the composition may comprise at least a monomer, and a chlorinated additive. Photo initiators may be used to allow for low temperature UV or other radiation curing. Other additives may be used to enhance functional features in various ways. In use, the present invention may be coated on a surface of EVA and then cured, and may be adhered to a substrate using only a layer of adhesive on the substrate, in contrast to the structures of the prior art, which require at least two sided adhesive application, among other complexities.

Claims

1. A 100% solids composition operable at room temperature and capable of radiation curing comprising: a monomer, selected to be at least one of a (meth)acrylate monomer and (meth)acrylate functional urethane oligomer; a chlorinated compound selected to be at least one of a chlorinated polyester, chlorinated rubber, and chlorinated polyolefin; and a photo initiator making up to 5% of the composition.

2. The 100% solids composition of claim 1 consisting of: 10-50% hexanediol diacrylate as the monomer; 10-40% chlorinated polyester as the chlorinated compound; 10-30% cyclic aliphatic diacrylate; 1-5% acidic methacrylate; and 1-5% photoinitiator.

3. The 100% solids composition of claim 1 consisting of: 10-50% hexanediol diacrylate as the monomer; 10-40% chlorinated polyester as the chlorinated compound; 10-30% cyclic aliphatic diacrylate; 1-5% acidic methacrylate; 5-35% modified epoxy diacrylate; and 1-5% photoinitiator.

4. The 100% solids composition of claim 1 consisting of: 60-99% methyl methacrylate as the monomer; 0-20% hexanediol diacrylate; 10-20% chlorinated polyolefin as the chlorinated compound; 1-20% acidic methacrylate; 1-5% NVC; and 1-5% photoinitiator.

5. The 100% solids composition of claim 1 consisting of: 10-30% hexanediol diacrylate as the monomer; 10-70% acrylic polymer; 10-20% chlorinated polyester as the chlorinated compound; 1-5% acidic methacrylate; and 1-5% photoinitiator.

6. The 100% solids composition of claim 1 consisting of: 10-40% hexanediol diacrylate as the monomer; 10-40% chlorinated polyester as the chlorinated compound; 10-20% cyclic aliphatic diacrylate; 10-20% SCEA; 1-10% NVC; and 1-5% photoinitiator.

7. The 100% solids composition of claim 1 consisting of: 10-40% hexanediol diacrylate as the monomer; 10-40% chlorinated polyester resin as the chlorinated compound; 1-5% acidic methacrylate; 10-20% SCEA; 1-10% NVC; and 1-5% photoinitiator.

8. The 100% solids composition of claim 1 further comprising 10-50% of the monomer, the monomer being at least one of hexanediol diacrylate and methyl methacrylate.

9. The 100% solids composition of claim 8 further comprising a plurality of different (meth)acrylate functional urethane oligomers, the combination of the plurality of different (meth)acrylate functional urethane oligomers making up 11-75% of the composition.

10. The 100% solids composition of claim 8 further comprising the chlorinated compound in a composition of 10-40%.

11. The 100% solids composition of claim 10 further comprising a plurality of different (meth)acrylate functional urethane oligomers.

12. The 100% solids composition of claim 11 wherein the plurality of oligomers comprises cyclic aliphatic diacrylate and acidic methacrylate.

13. The 100% solids composition of claim 11 wherein the plurality of oligomers comprises cyclic aliphatic diacrylate, acidic methacrylate, and modified epoxy diacrylate.

14. The 100% solids composition of claim 8 further comprising 10-30% cyclic aliphatic diacrylate.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG. 1 provides a flow chart of an embodiment of use of the present inventive composition.

DETAILED DESCRIPTION

[0015] The detailed description set forth below in connection with the appended drawings is intended as a description of presently preferred embodiments of the invention and does not represent the only forms in which the present invention may be constructed and/or utilized. The description sets forth the functions and the sequence of steps for constructing and operating the invention in connection with the illustrated embodiments.

[0016] This invention includes an adhesive/primer composition for use with EVA having a 100% solids composition with 0% solvent added and may function as the adhesive itself so only the contact substrate requires an adhesive coat. The composition of the present invention removes unnecessary and potentially harmful VOC's from the worker and environment, eliminates the need for high temperatures that are required of hot-melt adhesives and their resulting difficulties, and also removes a step in the adhesion process of footwear manufacturing. The present invention is usable at ambient room temperatures without any added temperature adjusting steps during use.

[0017] Generally, the present invention concerns a 100% solids, radiation curable adhesive formulation for adhesion to EVA. Further, in some embodiments, the present invention may be used as a primer as well as, or in alternative to adhesive. This formulation may have varying compositions, as discussed in detail below. However primarily the composition may comprise at least a monomer, and a chlorinated additive. Photo initiators may be used to allow for low temperature UV or other radiation curing. Other additives may be used to enhance functional features in various ways.

[0018] This 100% solids formulation does not require any solvents, as is required of the prior art. The formulations contemplated herein provide a number of advantages over the existing solutions. For example, the invention provides both an improved product and an improvement in manufacturing. The 100% solids composition uses no volatile organic compounds (VOCs) thereby making it a “greener” technology. Eliminating VOCs also creates a less hazardous and less expensive implementation. Further, the present invention eliminates steps from manufacturing by allowing room temperature, solvent free curing, and by eliminating the need for an adhesive directly applied to the cured adhesive/primer. Instead, an adhesive is only needed on the substrate to be applied to the EVA that is coated with the adhesive/primer of the present invention. This adhesive may be the composition of the present invention, or another adhesive. In many embodiments, a second adhesive is not needed, and the present inventive composition is sufficient to bond EVA to the substrate. These eliminated steps can result in cost savings and also energy savings (such as removal of an oven or less energy powering an incinerator), which in turn leads to a “greener” technology providing both a safer work environment and cost savings.

[0019] Speaking generally, in many, but not all embodiment of the present invention, the composition may include either an acrylate or methacrylate, diluents, and a photo initiator. For adhesion promotion to EVA, a chlorinated compound may also be necessary, such as chlorinated polyester or chlorinated polyolefin.

[0020] Typically, the present invention composition requires a monomer, such as a (meth)acrylate monomer or (meth)acrylate functional urethane oligomer. Further, the composition requires a chlorinated compound such as a chlorinated polyester, chlorinated rubber, and/or chlorinated polyolefin. Additionally, the photo initiator allows for curing via, for example, UV radiation.

[0021] As noted, the primary features of the present inventive composition are the a monomer, selected to be at least one of a (meth)acrylate monomer and (meth)acrylate functional urethane oligomer; a chlorinated compound selected to be at least one of a chlorinated polyester, chlorinated rubber, and chlorinated polyolefin; and a photo initiator. The specific compositions disclosed herein may, in many cases, have different additives interchanged or used in other embodiments, without straying from the scope of the present invention. The following non-limiting examples provide approximate ranges of 100% solids compositions of the present invention that have been used to successfully bind EVA to a contact substrate:

Example 1

[0022]

TABLE-US-00001 HDDA (hexanediol diacrylate) - monomer 10-50% Ebecryl 438 - chlorinated polyester 10-40% Ebecryl 130 - cyclic aliphatic diacrylate 10-30% Ebecryl 168 - acidic methacrylate 1-5% Irgacure 500 1-5%

Example 2

[0023]

TABLE-US-00002 HDDA (hexanediol diacrylate) - monomer 10-50% Ebecryl 436 - chlorinated polyester 10-40% Ebecryl 130 - cyclic aliphatic diacrylate 10-30% Ebecryl 168 - acidic methacrylate 1-5% Ebecryl 3418 - modified epoxy  5-35% diacrylate Irgacure 500 1-5%

Example 3

[0024]

TABLE-US-00003 MMA (Methyl Methacrylate - monomer 60-99% HDDA (hexanediol diacrylate) - monomer  0-20% DX-530p - chlorinated polyolefin  1-20% Ebecryl 168 - acidic methacrylate  0-20% NVC 1-5% Irgacure 500 1-5%

Example 4

[0025]

TABLE-US-00004 HDDA (hexanediol diacrylate) - monomer 10-30% Ebecryl 1710 - acrylic polymer 10-70% Ebecryl 438 - chlorinated polyester 10-20% Ebecryl 168 - acidic methacrylate 1-5% Irgacure 500 1-5%

Example 5

[0026]

TABLE-US-00005 HDDA (hexanediol diacrylate) - monomer 10-40% Ebecryl 438 - chlorinated polyester 10-40% Ebecryl 130 - cyclic aliphatic diacrylate 10-20% βCEA 10-20% NVC  1-10% Irgacure 500 1-5%

Example 6

[0027]

TABLE-US-00006 HDDA (hexanediol diacrylate) - monomer 10-40% Genomer 6050 - chlorinated polyester resin 10-40% Ebecryl 168 - acidic methacrylate 1-5% βCEA 10-20% NVC  1-10% Irgacure 500 1-5%

Example 7

[0028]

TABLE-US-00007 Genomer 1120 ( cyclic mono-functional 75-90% acrylate) Pergut S20 (chlorinated rubber)  8-20% Irgacure 500 0-5% βCEA   0-5%% CN 780 0-5%

[0029] Generally, it is known in the art that chlorinated materials such as chlorinated polyester or chlorinated polyolefins are designed to promote adhesion to specific substances. These substances include polyester, polypropylene, and other thermoplastic olefins (TPO). EVA is different from and not related to these categories of materials. Therefore, the compositions of the present invention demonstrated the unexpected result of being highly effective with use on EVA as a primer and adhesive.

[0030] It is believed that these formulations differ from current commercial formulations in omitting tri-functional acrylates and instead using mono and di-functional acrylate monomers. This allows the primer to retain thermoplasticity which allows the cured primer to flow more and wet with the PU/adhesive coated substrate after heat activation compared to prior art compositions. The tri-functional acrylates crosslink more than mono and di-functional acrylates, thus not being very flowable when attempting to bond to the heat activated adhesive surface. It is notable as well that EVA primers in the prior art utilize a solvent base, and are not 100% solids compositions.

[0031] Additionally, compared to the existing solvent borne formulations, this invention is also thicker, because the solvent borne formulations tend to lay down only a monolayer as the solvent is driven off, leaving only solids. With 100% solid formulations, everything disposed on the EVA material remains. This allows better surface wet-out and penetration at the primed surface/adhesive interface. Overall, there is much more contact between layers compared to a thin monolayer with prior art solvent based compositions.

[0032] In one embodiment of use, as illustrated in FIG. 1, the composition may be applied to an EVA surface, such as a sole of a shoe. This application may be by, for example, spraying, brushing, rolling, or the like. The inventive composition may then be radiation cured-typically UV cured. Once cured the surface is ready to be bonded with an adhesive, for example a polyurethane adhesive-coated upper shoe portion. This adhesive is then used to join the EVA with the mating surface. Optionally, an adhesive may be coated over the cured adhesive/primer of the present invention, but this additional adhesive is not required. Not including this second adhesive application cuts out a step when compared to the prior art process. It should be understood that this embodiment of use may use any variation of the inventive compositions disclosed herein without straying from the scope of this invention.

[0033] While several variations of the present invention have been illustrated by way of example in preferred or particular embodiments, it is apparent that further embodiments could be developed within the spirit and scope of the present invention, or the inventive concept thereof. However, it is to be expressly understood that such modifications and adaptations are within the spirit and scope of the present invention, and are inclusive, but not limited to the following appended claims as set forth. It is further to be understood that various aspects and embodiments may include elements and/or components that are similarly and equally applicable to other aspects and embodiments, without being limited to the particular aspect or embodiment to which they are described.