WO2008003190A1

WO2008003190A1 - Radiation curable adhesion promoter

Info

Publication number: WO2008003190A1
Application number: PCT/CN2006/003384
Authority: WO
Inventors: Jibing Lin; Jinshan Zhang
Original assignee: Shanghai Phichem Corporation
Priority date: 2006-06-26
Filing date: 2006-12-13
Publication date: 2008-01-10
Also published as: CN101096473A

Abstract

This invention relates to a new type of adhesion promoter, which in particular can be used in radiation curable coatings and adhesives. This adhesion promoter is obtained by fast reaction of alkoxysilanes containing mercapto groups, with monomers containing two or more acrylate or methacrylate groups, in the presence of organic amines under mild conditions. This adhesion promoter has adhesion promotive functional groups such as alkoxysilanes at one end, and polymerable groups of (meth)acrylate at the other end. The invention can be applied to coatings, inks and adhesives to improve adhesion between cured materials and substrates.

Description

RADIATION CURABLE ADHESION PROMOTER

Technical Field

This invention relates to a new type of radiation curable adhesion promoters, which can be applied to coatings, inks and adhesives to improve adhesion between cured materials and substrates. In particular they can be applied to radiation curable coatings and adhesives to promote adhesion between cured materials and substrates. Background Art

Radiation curable materials (including ultraviolet light curable materials and electron beam curable materials) have been developed rapidly in the past 20 years. They have been widely used in coatings, inks and adhesives etc since they provide high productivity, low energy consumption and zero environment pollution. Radiation curable materials are in general composed of four ingredients: oligomers, reactive monomers, photoinitiators and additives. Radiation curable materials are commonly first coated on the substrates, and cured via radiation resources (ultraviolet light or electron beam). The adhesion between the substrates and the cured radiation curable materials varies considerably from system to system. Adhesion promoters are the most common additives that improve adhesion between cured materials and substrates. The most common adhesion promoters are alkoxysilanes.

Alkoxysilane adhesion promoters are generally polymerization inactive-can not participate in polymerization reactions of monomers and oligomers during curing. As a result, their levels in formulations are considerably limited. The only commonly used polymerizable alkoxysilane adhesion promoter in industry is methacryloxypropyl trimethoxysilane. However it contains a certain level of starting material-allylmethacrylate, which is a volatile and odorous compound. Therefore its applicability is limited. See Waldman, Silane Coupling Agents Improving Performance, Modern Paints and Coatings, February, 1996.

On May 2, 1996, WO 96/12749 discloses an oligomer containing alkoxysilanes and optical fiber coating containing the oligomer. The silane oligomers are high in molecular weight (500-11000) and a high level of silane oligomers in the composition is needed (5-99%). Such oligomers are typically polyurethane materials.

On the other hand, US patent US6391463B1 discloses a new polymerisable alkoxysilane monomer, which is obtained by hydrosilylation reactions. Disclosure of Invention

Aiming at above-mentioned shortcomings of current technologies, it is an object of this invention to provide an easily made and industrialized new adhesion promoter, which is polymerizable and can be widely applied to radiation curable coatings, inks, and adhesives at high contents.

In order to solve above technical problems, this invention provides a radiation curable adhesion promoter, which is obtained by fast reaction of alkoxysilanes containing mercapto groups, with monomers containing two or more acrylate or methacrylate groups, in the presence of organic amine catalyst under mild conditions (for example at 65⁰C for one hour), as shown in Equation

1 :

(R₁

Equation 1

Above radiation curable adhesion promoter has (meth)acrylate at one end which is polymerable; and an alkoxysilane group at the other end which is adhesion promotive.

In contrast to current techniques, the radiation curable adhesion promoter of this invention due to its polymerization activity, are unrestricted in quantity in their application to coatings, inks, and adhesives. Particularly in radiation curable coatings, inks and adhesives use of above adhesion promoters in large quantities can greatly change adhesion power between cured materials and substrates. Modes for Carrying Out the Invention

This invention will be further described with following illustrative examples: Example 1

According to Equation 1, 19.6g of 3-mercapto propyl trimethylsilane, 22.6g of hexane-l,6-diol diacrylate and O.lg of diethylamine were added into a dry and clean reactor. The mixture was heated to 65⁰C under uniform stirring. 3-mercapto propyl trimethylsilane was completely reacted according to testing by gas chromatography. The resulting colorless liquid was radiation curable adhesion promoter A. Example 2-UV curable coating

50% aromatic polyurethane acrylate oligomer (RMAT 650)

42% hexane-l,6-diol diacrylate (HDDA)

3% 1 -hydroxy cyclohexyl phenyl ketone (Irgacure 184)

1% 2,4,6-trimethylρhenol (Irganox 1010)

4% radiation curable adhesion promoter A

Above ingredients were added successively into a reactor. After agitation at 60⁰C for two hours an UV curable coating was obtained via filtration. Its viscosity was 2100 cps at 25⁰C. This UV curable coating has good bonding to glass, metals, and some plastics. Example 3-UV curable ink

45% aromatic polyurethane acrylate oligomer (RMAT 650)

12% hexane-l,6-diol diacrylate (HDDA)

20% trimethlolpropane triacrylate (TMPTA)

15% white color paste (55% titanium dioxide dispersed in TMPTA)

3% 1 -hydroxy cyclohexyl phenyl ketone (Irgacure 184)

1% 2,4,6-trimethylphenol (Irganox 1010) 4% radiation curable adhesion promoter A

Above ingredients were added successively into a reactor. After agitation at 60⁰C for two hours an UV curable ink was obtained via filtration. Its viscosity was 1600 cps at 25⁰C. This UV curable ink has good bonding to glass, metals, and some plastics. Other colored inks can be made in a similar way to above. Example 4-Radiation curable adhesive

50% radiation curable adhesion promoter A

47% isobornyl acrylate (IBOA)

3% 1 -hydroxycyclohexyl phenyl ketone (Irgacure 184)

Above ingredients were added successively into a reactor. After agitation at 60⁰C for two hours an UV curable adhesive was obtained via filtration. Its viscosity was 400 cps at 25⁰C. The adhesive can be used in bonding metals and glass etc. with very tight adhesion.

Claims

1. A radiation curable adhesion promoter, which is obtained by fast reaction of alkoxysilanes containing mercapto groups, with monomers containing two or more acrylate or methacrylate groups, in the presence of organic amine catalyst under mild conditions,

2. A radiation curable coating, which contains 0.1-60% radiation curable promoters of claim 1 or/ and 2.

3. A radiation curable adhesive, which contains 0.1-99% radiation curable promoters of claim 1 or/and 2.

4. A radiation curable ink, which contains 0.1-10% radiation curable promoters of claim 1 or/and 2.