JPH03177479A - Adhesive for electrostatic hair setting - Google Patents

Abstract

PURPOSE:To obtain the title adhesive consisting of a composition obtained by adding viscosity-providing synthetic rubber latex to epoxy-modified aqueous acryl emulsion as main agent ingredients and curing agent ingredient containing an epoxy resin curing agent, having adhesion to coating face, bonding force, heat resistance, etc. CONSTITUTION:The objective adhesive having (A) main agent ingredient obtained by adding 5-50 pts.wt. (as a solid content) of viscosity-providing synthetic rubber latex (preferably containing 10-50 pts.wt. viscosity-providing resin in 100 pts.wt. solid content) to 100 pts.wt. solid content of epoxy-modified acrylic emulsion [preferably containing 1-30 pts.wt. epoxy resin in 100 pts.wt. solid content] and (B) curing agent ingredient containing epoxy resin curing agent at an amount of 5-30 pts.wt. as a solid content.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a two-component water-based emulsion adhesive for electrostatic flocking. This is an adhesive for electrostatic flocking that is suitable for painted iron plates having resin-based coatings, etc., and relates to adhesives that have adhesion to painted surfaces, adhesive strength, heat resistance, boiling resistance, etc.

(Prior art) Conventionally, painted steel plates using polybutadiene-based paints for rust prevention have been used for automobile interior parts, light electrical parts, etc., and as an adhesive for electrostatic flocking on the surface of these painted steel plates. Two-component solution type urethane adhesives were mainly used.

(Problems to be Solved by the Invention) There is a growing need for water-based adhesives. Therefore, attempts have been made to use aqueous emulsions such as acrylic emulsions, synthetic rubber latexes, ethylene-vinyl acetate copolymer emulsions, and aqueous urethane dispersions. However, these attempts have not been put into practical use because problems such as poor adhesion to painted surfaces, water resistance, heat resistance, and boiling resistance have not been overcome.

(Means for Solving the Problems) As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention have found that the main ingredient is an epoxy-modified aqueous acrylic emulsion mixed with tackifying synthetic rubber latex, and a curing agent. We discovered that by using an epoxy resin curing agent in combination with a two-component solvent-based urethane adhesive, it is possible to provide adhesion, adhesive strength, water resistance, heat resistance, boiling resistance, etc. comparable to that of two-component solvent-based urethane adhesives.Based on this knowledge, we developed this book. The invention was completed.

That is, the present invention provides (1) a base component containing 5 to 50 parts by weight of a tackifying synthetic rubber latex, including a solid content of 5 to 50 parts by weight, and an epoxy resin curing agent in a solid content of 100 parts by weight of an epoxy-modified aqueous acrylic emulsion; as 5-3
(2) an epoxy-modified aqueous acrylic emulsion, which comprises: (2) an epoxy-modified aqueous acrylic emulsion; The adhesive for electrostatic flocking according to (1) above, characterized in that it contains 1 to 30 parts by weight of epoxy resin, and (3) the tackifying synthetic rubber latex has a solid content of ioo and it parts in the solid content of the synthetic rubber latex. To,
The adhesive for electrostatic flocking according to (1) above, which contains 10 to 50 parts by weight of a tackifying resin, and (4)
The present invention provides an adhesive for electrostatic flocking according to (1) above, wherein the curing agent component is an aqueous emulsion or an aqueous solution.

The epoxy-modified acrylic emulsion used in the present invention is an acrylic emulsion containing an epoxy resin, for example, acrylic emulsion particles of epoxy resin dissolved in and reacted with epoxy resin monomers during emulsion polymerization of an aqueous acrylic emulsion. This is a composite emulsion designed to contain internal alloys. More specifically, there are acrylic compounds modified to have at least two epoxy groups. This can be prepared by reacting an emulsion containing an acrylic compound with a functional group with an epoxy resin having a group reactive with the functional group.

The acrylic emulsion used here is one used in ordinary adhesives and is not particularly limited, but for example, it may be a copolymer emulsion of the following hard monomer, soft monomer, and functional group monomer.

Specifically, examples of the hard monomer include one or more of styrene, methyl methacrylate, acrylonitrile, vinyl acetate, and the like. Examples of the soft monomer include one or more of methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and the like. Examples of functional monomers include those having a carboxyl group, such as acrylamide acid; those having an amide group, such as acrylamide, methacrylamide, and maleinamide; and those having a hydroxyl group, such as hydroxyethyl acrylate, hydroxyethyl methacrylate, and hydroxypropyl. Examples of acrylates having an N-methylolamide group include N-methylol acrylamide and the like. The preferred composition ratio of these is 3 as the hard monomer.
0 to 60 parts by weight, 20 to 50 parts as soft monomer
The amount ranges from 1 to 10 parts by weight as the functional monomer.

A typical example of the preparation of this epoxy-modified aqueous acrylic emulsion is as follows: 30 to 45 parts by weight of styrene, 30 to 50 parts by weight of butyl acrylate, 2 parts each of methacrylic acid, hydroxyethyl acrylate, and acrylamide as functional group monomers, bisphenol type Monomers in which 10 to 30 parts by weight of epoxy resin are mixed and dissolved are gradually added to distilled water containing an emulsifier while stirring. On the other hand, as in the usual emulsion polymerization method, distilled water and an emulsifier are charged into a flask, and nitrogen Stir under a seal, raise the temperature to 60-80°C, and dose the polymerization initiator.

An emulsion of the above-mentioned monomers, etc. is continuously administered to this over several hours, and after treatment with the remaining monomer, it is cooled, neutralized with alkali, and thickened with polyacrylic acid or polyvinyl alcohol as necessary.

In this case, the epoxy resin component is preferably contained in 1 to 30 parts by weight, more preferably 5 to IO parts by weight, in 100 parts by weight of the solid content of the epoxy-modified aqueous acrylic emulsion. If this epoxy resin component is too small, no improvement in adhesive strength, heat resistance, boiling resistance, etc. will be observed, and if it is too large, it will act as a kind of polymer plasticizer, exhibiting stickiness and significantly reducing stability during emulsion polymerization. It is damaged and lacks practicality.

The epoxy resin component used in this epoxy-modified aqueous acrylic emulsion is not particularly limited, but bisphenol-type epoxy resins are the most practical in terms of stability during emulsion polymerization. This epoxy resin has, for example, an epoxy equivalent of 180 to 2701 and a viscosity of 5.
~150 voids (25°C) is preferred.

The tackifying synthetic rubber latex used in the present invention is a synthetic rubber latex containing a tackifying resin, and the tackifying resin is io to 50 parts by weight in 100 parts by weight of the solid content of the synthetic rubber latex. Preferably 15~
More preferably 30 parts by weight. More specifically, for example, 100 parts by weight of tackifying resin, 2 to 10 parts by weight of surfactant,
A homogeneous solution containing 10 to 100 parts by weight of an organic solvent is heated and stirred at high speed to form a synthetic rubber latex of 100 to 1 part by weight.
000 parts by weight can be added continuously.

If the amount of the tackifier resin is too small, it will lack adhesion with the polybutadiene paint, and if it is too large, it will become sticky, causing problems in adhesive strength, heat resistance, and boiling resistance.

Examples of the above tackifier resin include Ester Gum S-1
00 (trade name, glycerin ester of modified rosin, manufactured by Arayo Kagaku Kogyo ■), Ester Gum H (trade name, glycerin ester of hydrogenated rosin, manufactured by Arayo Kagaku Kogyo ■), YS Polyster 2100 (trade name, terpene phenol) Examples of surfactants include Neocol P (trade name, manufactured by Dai-ichi Kogyo Seiyaku), Neugen EA-126 (trade name, manufactured by Daiichi Kogyo Seiyaku), etc. It will be done. Examples of organic solvents include toluene, n-hexane, dioctyl phthalate, and ethanol.

The curing agent component containing the epoxy resin curing agent used in the present invention is not particularly limited, and any dispersion or water-soluble type may be used. version, imidazole aqueous solution, polyamide aqueous solution, etc. Among these, a low-volatility imidazole aqueous solution is more preferred.

Furthermore, in the present invention, the blending ratio of the tackifying synthetic rubber to 100 parts by weight of solid content is 5 to 50 parts by weight as solid content.
The amount ranges from 10 to 30 parts by weight, preferably from 10 to 30 parts by weight. In addition, if the tackifying synthetic rubber latex is less than 5 parts by weight, it will lack adhesion and adhesion to the polybutadiene-based painted steel plate, and if it is more than 50 parts by weight, the heat resistance and boiling resistance will be significantly reduced, causing practical problems. .

The blending ratio of the epoxy resin curing agent to 100 parts by weight of the solid content of the epoxy-modified acrylic emulsion is preferably in the range of 5 to 30 parts by weight, more preferably 7 to 30 parts by weight.
The range is 15 parts by weight. If the amount is less than 5 parts by weight, the adhesive will not cure sufficiently and will lack adhesive strength, heat resistance, and boiling resistance.
When the amount is more than 30 parts by weight, the viscosity decreases due to a decrease in adhesive concentration, causing uneven flocking, resulting in quality problems and lack of practicality.

In addition, when using the adhesive of the present invention, additives such as a coloring agent, an antifoaming agent, an antiaging agent, a surfactant, and a thickening agent may be added as necessary.

(Effects of the Invention) The adhesive for electrostatic flocking of the present invention is a mixture of epoxy-modified water-based acrylic emulsion and tackifying synthetic rubber latex, and has extremely high adhesion to painted iron plates using polybutadiene paints. It has excellent adhesive strength, heat resistance, boiling resistance, etc. due to the combination of an epoxy resin curing agent, and since it is an aqueous emulsion type, it is also excellent in terms of preventing environmental pollution, and is of high practical value.

(Example) Next, the present invention will be explained in more detail based on examples.

In addition, unless otherwise specified below, parts or percentages are parts by weight or percentages by weight.

Examples 1 to 9 (Preparation of epoxy-modified aqueous acrylic emulsion) Table 1
100 parts of a mixture of the monomer and epoxy resin shown in Figure 1 and a chain transfer agent were continuously added to 50 parts of distilled water and 0.3 parts of sodium dodecylbenzenesulfonate under stirring conditions to emulsify.

Separately, 50 parts of distilled water and 0.2 part of sodium dodecylbenzenesulfonate were placed in a flask, stirred under a nitrogen blanket, heated to 70°C, and then 0.5 part of potassium persulfate was added. Next, an emulsion of the monomers, etc., was continuously administered to this solution over 4 hours, and the remaining monomers were further polymerized at the same temperature for 4 hours, cooled to 30°C or less, adjusted to pH 7 with 14% aqueous ammonia, and the solid content was reduced. A 50% epoxy modified aqueous acrylic emulsion was obtained.

In order to thicken the thus obtained emulsion to a viscosity suitable for air spray application, a partially saponified polyvinyl alcohol aqueous solution was used to obtain an epoxy-modified acrylic emulsion whose viscosity was adjusted to 4000 cps.

Table * Tobu Kasei Seizo, trade name Kobototo YD-128 (viscosity 11,000 to 12,000 cps.

Epoxy equivalent: 1849/eq) (Preparation of tackified synthetic rubber latex) The composition shown in Table 2 was charged into a 14 volume flask equipped with a condenser and a stirrer, and dissolved by heating at 80°C. After confirming uniform dissolution, 60
The temperature was lowered to 0.degree. C., and the stirring speed was set at 30 rpm. Next, Structbond 1351 was used as synthetic rubber latex.
(Mitsui Toatsu Chemical SBR latex, solid content 48%,
Viscosity 150 cps, pH 7.0, glass transition temperature -30
℃) 600 parts were continuously dropped at a speed of 100 g/min,
A tackifying synthetic rubber latex (solid content 53%, pH 7.0) used in the present invention was obtained.

The tackifying synthetic rubber latexes A, B, and C shown in Table 2 were blended with the epoxy-modified acrylic emulsions A and B shown in Table 1 in the proportions shown in Table 3, and the mixture was thoroughly stirred and mixed. Next, a partially saponified polyvinyl alcohol aqueous solution (manufactured by Kikuri Rare,
20% aqueous solution of PVA205) was added to produce 4000 cps.
The viscosity was adjusted to

An epoxy resin curing agent in the proportion shown in Table 3 was added to this mixed emulsion to obtain an adhesive for electrostatic flocking of the present invention.

The physical properties of this adhesive were evaluated by the method shown below, and the results are shown in Table 4.

(1) Electrostatic flocking This adhesive was applied uniformly at 200 g/rrl' to a painted iron plate using a polybutadiene paint using an air spray. Next, nylon pile (3 denyl, length 0.5 mm)
) was flocked by applying a voltage of 30 KV and dried for 45 minutes in a 70° C. hot air dryer to produce an electrostatic flocked sample for evaluation of physical properties.

(2) Evaluation of Physical Properties 2-1) Adhesive Electrostatic Flocking A cut of 1 mm square was made in the vertical and horizontal directions on the surface of the sample using a cutter knife to create 100 goban stitches. Next, apply Sekisui cellophane adhesive tape on top of it, and calculate the number of stitches remaining on the base material when it is forcibly removed.
/ Displayed as 100. By the way, 100/100 indicates complete adhesion.

0/100 means all peeling.

2-2) Boiling Resistance Electrostatic flocking processed samples were immersed in boiling water for 200 hours, left to cool at room temperature for 1 hour, and then peeled off the sample surface using a flat head screwdriver to indicate the presence or absence of peeling as shown below.

○... Not peeled off at all Δ... Partially peeled ×... Easily peeled off 2-3) Adhesive strength Apply g/rd uniformly to a painted iron plate using polybutadiene paint, and immediately apply it with a cotton cloth. Glue #40 cloth, 70
The sample was dried for 45 minutes in a hot air dryer at ℃ to prepare a sample for physical property evaluation.

Next, this sample was cut to a length of 100 mm and a width of 25 mm to prepare a sample for adhesion strength measurement using a Tensilon tensile tester.

The sample was heated at 23±2°C in a constant temperature room of R865% for 200 minutes.
It was peeled off at an angle of 180° C. at a speed of mm/min, and its strength was expressed in kg725 mm.

2-4) Heat resistance The same test as in 2-3) above was carried out in an atmosphere of 90°C, and the results were displayed in the same manner.

2-5) Presence or absence of electrostatic flocking unevenness The flocked surface was observed and displayed as shown below.

○...The flocked surface has a uniform finish and there are no dark and light areas ×...The flocked surface has light and dark areas Comparative Examples 1 to 5 Similarly to Examples 1 to 9, epoxy-modified synthetic rubber latex A and B shown in Table 1 , C and epoxy resin curing agents A, B
were used in the compositions shown in Table 3, and the physical properties were evaluated in the same manner as in the above Examples, and the results are shown in Table 4.

Table *40% epoxy resin curing agent A...Curesol 2MZ (trade name, imidazole type, manufactured by Shikoku Kasei ■, boiling point 178°C) 40 parts, SN Thickener A-803 (trade name, manufactured by San Nobuco ■, urethane-modified polyether) Curing agent B: 3 parts of mold thickener) dissolved in 57 parts of water...Evolution EB-1 (trade name, modified aliphatic polyamine desversion, Kanebo N S C [) solid content 40%, viscosity 200 cps, pH 10.5, fully aminated 117) As is clear from Table 4, the electrostatic flocking adhesive of the present invention is effective in flocking coated iron plates using polybutadiene paints, unlike conventional water-based emulsions. It has excellent adhesion, adhesion, heat resistance, boiling resistance, etc., has very little flocking unevenness, and since it is an aqueous emulsion type, it is also excellent in terms of environmental pollution, and its practical value is extremely high and its significance is great.

Claims (4)

[Claims] (1) Based on 100 parts by weight of the solid content of the epoxy-modified aqueous acrylic emulsion, a main component containing 5 to 50 parts by weight of a tackifying synthetic rubber latex as a solid content and 5 to 30 parts by weight of an epoxy resin curing agent as a solid content. An adhesive for electrostatic flocking, comprising a curing agent component. (2) The electrostatic flocking according to claim (1), wherein the epoxy-modified aqueous acrylic emulsion contains 1 to 30 parts by weight of epoxy resin in 100 parts by weight of the solid content of the epoxy-modified acrylic emulsion. Adhesive for use. (3) For electrostatic flocking according to claim (1), wherein the tackifying synthetic rubber latex contains 10 to 50 parts by weight of tackifying resin in 100 parts by weight of the solid content of the synthetic rubber latex. glue. (4) The adhesive for electrostatic flocking according to claim (1), wherein the curing agent component is an aqueous emulsion or an aqueous solution.