JPS60137978A - Aqueous contact adhesive - Google Patents

Abstract

PURPOSE:To provide titled adhesive of high-level initial bond strength long in thickness-retaining time, free from any danger of fire and poisening, having specific properties, for application to metals etc., consisting mainly of a polymer emulsion prepared by radical polymerization of alpha,beta-monoethylenic unsaturated monomer in water. CONSTITUTION:The objective adhesive with the glass transition temperature (Tg) and average molecular weight determined by gel permeation chromatography, of the inner layer polymer component (A1) being 0-40 deg.C and 1X10<3>- 1X10<5>, respectively, and the Tg and average size of dispersed particles of the outer polymer component (A2) being -60-10 deg.C and 0.5-1.5mu, respectively, can be obtained by using a polymer emulsion prepared by radical polymerization of alpha, beta-monoethylenic unsaturated monomer in water (e.g. consisting of vinyl epoxy-unsaturated carboxylic acid). EFFECT:Giving both high water-and heat-resistant bond strength.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention discloses that α,β-monoethylenically unsaturated f1!
The present invention relates to a contact adhesive whose main ingredient is a polymer emulsion obtained by radical polymerization of a polymer.

Conventionally, the mainstream contact adhesives have been rubber-based, particularly solvent-based or aqueous emulsion-based adhesives mainly composed of Chlorobrengo J and yarn. The former uses a large amount of organic solvent, so there is a risk of fire, dryness, etc., and there is also a +1 risk of environmental pollution.
There is a strong desire to shift to water-based systems due to resource conservation issues. On the other hand, although some of the latter has been put into practical use,
& Because the waiting time is short, there are problems with workability, and the adhesion to non-porous adherends such as eyelids and metal surfaces is poor. In addition, water-based contact adhesives for acrylic emulsion threads have been introduced in recent years, but they have a short adhesive retention time and are inferior in initial adhesive strength, water-resistant adhesive strength, and heat-resistant adhesive strength.

The present inventors have overcome the shortcomings of such conventional contact adhesives, and have created a product that does not pose the risk of fire or poisoning, has a long adhesive retention time, and has excellent initial adhesive strength, water-resistant adhesive strength, and heat-resistant adhesive strength. As a result of intensive research into water-based contact adhesives, we have determined that the polymer emulsion that is the main ingredient of the adhesive has a Tg within a specific range.
The above 3ff can be adjusted by adjusting the molecular weight, particle structure, and sperm diameter.
We have discovered a scale that satisfies the characteristic f11, and have completed the present invention.

That is, the adhesive of the present invention is a polymer emulsion whose main component is radically polymerized in an α,β-monoethylenically inert saturated monomer, and the polymer dispersion ti> is 4. ) Consisting of at least two or more multilayers, the polymer component (A1) constituting the inner layer has a Tg of 0°C to 40°C and an average molecular weight (Mw) measured by gel permini-silon chromatography of I x 103 ~lXIO
3, and the Tg of the polymer component (A2) constituting the outer layer is
The present invention provides an aqueous contact adhesive characterized in that the average particle diameter of the dispersed particles is 1 at 0° C. to -1θ° C. and the average particle size of the dispersed particles is in the range of 0.5 to 1.5 μm.

The α,β-monoethylenically unsaturated monomers used in the present invention include vinyl esters such as vinyl acetate and vinyl propionate; methyl (meth)acrylate, ethyl (
Alkyl (meth)acrylates such as meth)acrylate and butyl (meth)acrylate; styrene, acrylonitrile, ethylene, propylene, etc.; unsaturated carboxylic acids such as (meth)acrylic acid, itaconic acid, maleic acid, and fumaric acid; Salt IJl, half esters; Vinyl amides such as (meth)acrylamide, N-medylol (meth)acrylamide, and diaseptone acrylamide; Vinyl amines such as alkylamino (meth)acrylate; Vinyl epoxies such as glycidyl (meth)acrylate vinylsilanes such as vinyltrimethoxysilane and vinyltris(2-methoxyethoxy)silane; and the like.

Performance of the finally obtained polymer emulsilon as a contact adhesive, i.e. initial adhesive strength, water resistant adhesive strength, i4
Thermal adhesive strength (adhesion strength mainly includes shear strength and peel strength)
In order to maintain a high level of temperature, one layer (g) of the polymer component (A1) constituting the innermost layer must be heated to a temperature of 0°C to 40°C, preferably 0°C.
~30°C, and average molecular weight (MW) as measured by gel permeability chromatography x 1
03~lXl0'', preferably 5X10''~5X]04
It needs to be within the range. It is also essential that the TR of the polymer component (A2) constituting the outer layer is -60°C to -10°C, preferably -55°C to -15°C. In addition, 50% to 95% by weight of the polymer components (81) and (A2)
Weight%, preferably 60% to 95% by weight is 5X10
It is desirable to have an average molecular m (Mw) of ~10x10s.

Here, the polymer component (AI) constituting the inner layer is effective in improving the initial adhesion strength (fusion bond strength) and peel strength, and the high molecular weight portion of the polymer dispersed particles (Fact J :
A2 and flF) are particularly important for shear strength and water resistance,
Effectively works to improve heat-resistant adhesive strength.

Furthermore, in order to provide improved drying properties and long adhesion retention times, which are essential properties for contact adhesives, the particle size of the polymer emulsion must be within a certain range, and the average particle size of the dispersed particles must be within a certain range. The thickness is preferably 0.5 to 1.5 μm, preferably 0.6 to 1.2 μm. When the average particle size is less than 0.5 μm, when applied to an adherend,
Reflection formation from the surface is rapid, impeding workability, and adhesive retention time is also short, making it unsuitable for practical use. On the other hand, if the average particle diameter exceeds 1.5 μm, the stability of the obtained polymer emulsion will be poor, and mechanical and storage stability will be significantly impaired, which is also undesirable.

The Tg of the polymer components (A1) and (A2) is lightning conductive;
The above α,β-monoethylenically unsaturated monomer is 3! !
"+!' is opened by polymerization. On the other hand, to adjust the molecular weight, a known and conventional method can be used, that is, when obtaining a low molecular weight polymer, a known chain transfer agent can be appropriately used. In addition, when obtaining a high molecular weight polymer, it can be obtained by appropriately using known and commonly used methods such as the amount of polymerization catalyst and reaction conditions, and means such as crosslinking.

On the other hand, the average particle diameter of dispersed spermatozoa can be adjusted to 0.5 to 1.5 μm by making full use of a known emulsion polymerization method.

The polymer emulsion, which is the main component of the adhesive of the present invention, is conventionally produced by a well-known and commonly used emulsion polymerization method. For example, emulsion polymerization using a radical-forming catalyst in water in the presence of an anionic emulsifier such as sodium dodecylbenzenesulfonate, a nonionic emulsifier such as polyoxyethylene nonylphenol ether, or a cationic emulsifier such as laurylpyridinium chloride. It will be carried out in It may also be produced without using any emulsifier or in the presence of an emulsifying dispersant such as a water-soluble oligomer or polymer.

As an emulsion polymerization method, first the inner layer polymer component (
A1) and then the outer layer, the polymer component (
A2) is preferably made of steel. The emulsifier or emulsifying dispersant used at this time is preferably used when producing the polymer component (A1) into steel, but may be added in small amounts at the stage of obtaining the polymer component (A2). Such a polymer emulsion has a polymer component (A2) with a polymer component (A1) as a core.
It is composed of at least two layers having (A1) and (A2) as basic structural units so that the debris is formed. However, this is by no means limited to two-stage polymerization, and it goes without saying that multi-stage polymerization in which copolymerization reactions to obtain the polymer component (A() or (A2)) are repeated is also possible. In this case, it is important that the outermost layer is composed of the polymer component (A2).The polymer emulsion thus obtained has good adhesion retention time, initial adhesive strength, and water- and heat-resistant adhesive strength as a contact adhesive. However, in order to particularly improve the water and heat resistant adhesive strength, the polymer component (Al) is combined with an α,β-monoethylenically unsaturated monomer (Ml) having a reactive polar group. It is a copolymer with α,β-monoethylenically unsaturated tIL-containing substance containing no polymer component (A
2) contains a polar group reactive with an α,β-monoethyl, lenically unsaturated IT polymer (M2) containing a polar group reactive with a reactive polar group of the width of the polymer component (81). Not α.

eFiEL is a polymer emulsion consisting of a copolymer with β-monoethylenically unsaturated tB-mer.

Here, α, β- containing reactive polar groups in the molecule
Typical monoethylenically unsaturated monomers l) and (M2) are the above-mentioned α,β-monoethylenically unsaturated monomers l) and (M2).
Among the t-isomers, there are unsaturated carboxylic acids, vinylamides, vinylamines, vinylepoxies, vinylsilanes, and the like.

Combinations of these reactive polar group-containing monomers (Ml) and (M2) include vinyl epoxy-unsaturated carboxylic acids or hydroxyl group-containing vinyl compounds, vinyl epoxies-vinyl amides or amine derivatives, and vinyl silanes-unsaturated Examples include saturated carboxylic acids or hydroxyl group-containing vinyl compounds, or combinations of vinylsilanes-vinylamides or vinylamines.

The solid content of the polymer emulsion thus obtained may generally be 30 to 70% by weight, but is preferably 50 to 65% by weight for practical purposes.

The obtained polymer emulsion can be used as a contact adhesive as it is, but the polymer emulsion is used as a main ingredient, and if necessary, a tackifier, a thermosetting resin, a thickener, a pigment, a filler, etc. are added. il! ii may be added and used.

Next, the present invention will be specifically described with reference to Examples.

Hereinafter, parts and percentages are based on weight unless otherwise specified.

Example 1 60 parts of ionized water and Neogen R (
0.8 part of emulsifier (manufactured by Daiichi Kogyo Seiyaku A11) was added and stirred. After keeping the internal temperature at 80°C and introducing nitrogen gas into the container, 5 parts of ethyl acrylate, 13 parts of methyl acrylate, 2 parts of acrylic acid, and 0 parts of lauryl mercaptan were added.
．． 2 parts of the mixture and a mixture of 0.2 parts of potassium persulfate and 3 parts of deionized water were each injected over a period of about 30 minutes and held at the same temperature for an additional hour to prepare the first stage. The polymerization reaction was completed.

Thereafter, while maintaining the internal temperature at 65° C., a mixture of 55 parts of n-butyl acrylate and 25 parts of ethyl acrylate, and a mixture of 0.1 part of potassium persulfate and 3 parts of deionized water were heated separately for about 2 hours. The copolymer emulsilin was injected into the solution, kept at the same temperature for 2 hours, and then cooled to obtain the desired copolymer emulsilin. Its properties are shown in Table-1.

Example 2 Into the same reaction vessel as in Example 1, 60 parts of deionized water and 18 parts of Neogen R0 were charged, and the internal temperature was maintained at 80°C.
5 parts of ethyl acrylate, 13 parts of methyl acrylate,
A mixture of 2 parts acrylic acid and 0.2 parts lauryl mercaptan with 0.2 parts potassium persulfate and 3 parts deionized water
and a mixture consisting of 30 parts each, each taking about 30 minutes;
The same temperature was further maintained for 1 hour to complete the first stage polymerization reaction.

Thereafter, while maintaining the internal temperature at 65°C, a mixture of 55 parts of n-butyl acrylate, 25 parts of ethyl acrylate, and 1.1 part of glycidyl methacrylate was added to 0.0 parts of potassium persulfate.
A mixture of 1 part of deionized water and 3 parts of deionized water was separately injected over a period of about 2 hours, and the mixture was further maintained at the same temperature for 2 hours and then cooled to obtain the desired copolymer emulsion. Its properties are shown in Table-1.

Example 3 Into the same reaction vessel as in Example 1, 60 parts of deionized water and 88 parts of Neogen RO were charged, and the internal temperature was maintained at 80°C.
5 parts of ethyl acrylate, 13 parts of methyl acrylate,
A mixture of 2 parts of acrylic acid and 0.2 parts of lauryl mercaptan, 0.2 parts of potassium persulfate, and 3 parts of deionized water was injected separately over approximately 30 minutes and maintained at the same temperature. The first stage polymerization reaction was completed.

Next, the internal temperature was maintained at 65°C, and n-butyl acrylate 5
5 parts of ethyl acrylate, 1-25 parts of vinyltris (2
- A mixture of 0.2 parts of methoxyethoxy)silane and 0.1 part of potassium persulfate and 3 parts of deionized water are injected separately over a period of approximately 2 hours and held at the same temperature for an additional 2 hours. Then, the desired copolymer emulsilone was obtained by cooling. Its properties are shown in Table-1.

Comparative Example 1 A copolymer emulsilon having an average molecular weight of N7X10S in the inner layer was obtained by using the same composition as in Example 1 except that lauryl mercaptan was not added and all other compositions and polymerization conditions were the same as in Example 1.

Its properties are shown in Table-1.

Comparative Example 2 62 parts of deionized water and 2 parts of Neogen R3 were put into the same reaction vessel as in Example 1, the internal temperature was maintained at 80°C, and 5 parts of ethyl acrylate, 13 parts of methyl acrylate, and 2 parts of acrylic acid were added. and a mixture of 0.2 parts of lauryl mercaptan, 0.2 parts of potassium persulfate, and 3 parts of deionized water were each injected over a period of approximately 30 minutes and held at the same temperature for an additional hour. The first stage polymerization reaction was completed.

Thereafter, while maintaining the internal temperature at 65°C, a mixture of 3 parts of Neogen R and 5 parts of deionized water was added, followed by a mixture of 55 parts of n-butyl acrylate and 25 parts of ethyl acrylate, and 0.1 parts of potassium persulfate. and 3 parts of deionized water were injected separately over a period of about 2 hours, held at the same temperature for an additional 2 hours, and then cooled to form a mixture with an average particle size of 0.2 μm. A polymer emulsion was obtained.

Comparative Example 3 Into a reaction vessel similar to Example 1, 60 parts of deionized water and 18 parts of Neogen R0 were charged, and the internal temperature was maintained at 65°C.
A mixture of 1-55 parts of n-butyl acrylate, 30 parts of ethyl acrylate, 13 parts of methyl acrylate, 2 parts of acrylic acid and 0.2 parts of lauryl mercaptan, and 0.3 parts of potassium persulfate and 6 parts of deionized water. It took about 2 hours and 30 minutes to inject each sample, and the mixture was further maintained at the same temperature for 2 hours and then cooled to obtain a copolymer emulsion for comparison.

IL shark example 4 Comparative example 3 except that the monomers used were 55 parts of n-butyl acrylate I, 30 parts of ethyl acrylate, 13 parts of ethyl acrylate, 2 parts of acrylic acid, and 1 part of glycidyl methacrylate. A copolymer emulcillin for comparison was obtained in the same manner as in Example 3.

Each property item in Table 1 was measured by the method shown below.

(1) 74 TF of the polymer was not actually measured but calculated by the method described in the following literature.

・Ifull, 8m, Ph5ics Soc, 1.
(3), I23 (1956)-Polym
er 1landhook-ON, Dig, 34.
131 (+962) (2) Average molecular weight and molecular weight distribution i'Jll using Waters GPC200 model (manufactured by Waters, gel permeation chromatography)
+ @weight average molecule li (M
W).

+311i) Column diameter Measured using a JEM-30C superscope (manufactured by JEOL Ltd., Denshi 1j Microscope).

Application example 1 Adhesive was applied to one side of each of two cover boards (solid content coating amount: approx. 60 g/rrj on one side), and the adhesive was applied at room temperature (23°C, 65% R1).
1) After taking an open time in the atmosphere of 1), the coated surfaces (25w x 25wn) of the cover material were pasted together, and 3k
Immediately after pressing at a pressure of f/CIII for 30 seconds, the strength immediately after adhesion (green strength) was measured using an Olsen type universal testing machine, and the IIE compressive shear strength was measured according to JIS K-6go4. Table 2 shows the surface, adhesive used, open time, and test results.

Application example 2: Apply adhesive to each side of two cover boards. After 30 minutes of open time in an atmosphere of 23°C and 65% RH, the solid content applied on each side was 60 g/nf). Paste the coated side (25 years old x 25+++s) and 3k
Clamp for 30 seconds at a pressure of g/c+a, and then press under the same atmosphere for 7
After curing for one day, the shear strength was measured under the same conditions as the normal strength. Further, the cured samples were immersed in water for 24 hours, and the water shear strength was measured while still wet.

The results are shown in Table-3.

Application example 3 Solid content coating amount is approximately 60% on each side of steel plate and canvas
Apply adhesive so that it becomes g/rd, 23℃, 65%
After 30 minutes of oven time under RH atmosphere,
The coated surface (25 days x 150 days) is pasted together and weighs 3 kg/
After being compressed with a pressure of 100 ml and curing in the same atmosphere for 70 hours,
After being left for 60 minutes at the measurement temperature shown in Table 4, the peel strength was 180" at the same temperature (tensile speed: l 54mm/mi)
n) was measured. The results are shown in Table 4.

Claims (1)

[Claims] A polymer emulsion whose main component is radically polymerized in an α,θ-monoethylenically inert saturated monomer, in which the polymer dispersed particles are composed of at least two or more multilayers, and the inner layer The glass transition temperature (Tg) of the polymer component (81) constituting is 0°C to 40°C and the average molecular P measured by gel permeation chromatography.
is 1×103 to IXII+”, and the glass transition temperature (Tg) of the polymer component (A2) constituting the outer layer is −60
An improved aqueous contact adhesive characterized in that the average particle size of the dispersed particles is in the range of 0.5 to 1.5 μm.