JPH07100783B2 - Adhesive composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an aqueous emulsion type adhesive for electrostatic flocking of a polyolefin film or foam.

More specifically, the present invention relates to an electrostatic flocking adhesive that has excellent adhesion to polyolefin and the flocked body after adhesion has excellent abrasion resistance.

[Conventional technology]

As a polyolefin adhesive represented by polyethylene, polypropylene and the like, a solvent type adhesive, an aqueous emulsion type adhesive, a hot melt type adhesive or the like has been conventionally used.

As the solvent-type adhesive, an adhesive containing a synthetic rubber-based, natural rubber-based, acrylic-based, urethane-based, or polyester-based resin as a main component, and in some cases, a tackifying resin dissolved in an organic solvent Is used. As the organic solvent, hydrocarbon-based, halogenated hydrocarbon-based, alcohol-based, ether-based, acetal-based, ketone-based, ester-based solvents, etc. may be used alone or in combination of several kinds.

Aqueous emulsion type adhesives include vinyl acetate emulsion, vinyl acetate-ethylene copolymer emulsion,
A vinyl acetate-acrylic copolymer emulsion, a synthetic rubber latex, a natural rubber latex, a urethane latex and the like, and an adhesive obtained by mixing a plasticizer, a tackifying resin and the like in an aqueous emulsion of these are used.

Examples of hot-melt adhesives include vinyl acetate-ethylene copolymer (referred to as EVA), styrene-butadiene-styrene block polymer (referred to as SBS), and styrene-ethylene-butadiene-styrene block polymer (referred to as SEBS). An adhesive containing tackifying resin, waxes, etc. as a main component is used.

[Problems to be solved by the invention]

Solvent-type adhesive not only has problems of industrial hygiene and environmental pollution due to scattering of organic solvent during work, but as is well known, electrostatic flocking causes fine piles to fly with a high voltage,
Since it is a processing method for planting an adhesive layer, the risk of fire is extremely high, and at present, it has only a proven track record for flocking small areas.

Further, as a problem in operation, the drying property of the adhesive layer due to the scattering of the organic solvent becomes a problem. That is, the concentration of the adhesive increases due to solvent scattering, the pile does not completely stick into the adhesive layer,
Since flocking unevenness occurs, it is indispensable to process flocking in a very short time, which is a practical problem.

The water-based emulsion adhesive lacks adhesion to polyolefin, and at the same time, it has problems of heat resistance, moisture resistance, and abrasion resistance. These problems are caused by the fact that all of the aqueous emulsion type adhesives currently commercially available for polyolefins have a so-called adhesive system in which the adhesiveness is physically improved by giving tackiness. It is believed that

The hot-melt adhesive is not suitable for electrostatic flocking due to the processing process, and it can be said that it has no actual results for this field.

That is, the hot melt resin is melted at a high temperature and applied, but at the same time as the application, it is considered that it is caused by the influence of the outside air temperature, solidification starts, and the piles that fly up are not sufficiently pierced into the adhesive layer. If flocking becomes possible under conditions of high temperature, the problem of pile alteration at high temperature will occur, which is a practical problem.

The purpose of the present invention is environmental pollution by an organic solvent, the risk of fire, there is no concern of occupational hygiene problems, adhesion to the film or foam of the polyolefin that was conventionally difficult to adhere, adhesion, Another object of the present invention is to provide an adhesive having excellent heat resistance and the like, which, when used for electrostatic flocking, gives a flocked body having excellent wear resistance and water resistance.

[Means for solving problems]

As a result of intensive studies to solve the above problems, the present inventors have found that a styrene-butadiene copolymer latex compound containing an adhesive resin in an aqueous emulsion, a chlorinated polyolefin, and a rosin-based aqueous emulsion type adhesive. It has been found that the combination of and is extremely effective, and the present invention has been completed.

That is, the present invention is based on (a) an aqueous emulsion and 100 parts by weight of this solid content, and (b) a styrene-butadiene copolymer latex compound containing a tackifying resin as a solid content of 5 to 5.
100 parts by weight, (c) 0.1 to 10 parts by weight of chlorinated polyolefin as a solid content, (d) 5 to 50 parts by weight of rosin-based aqueous emulsion adhesive as a solid content, (a) (b) (c) above An adhesive composition for electrostatic flocking of a polyolefin-based material, which comprises (d).

Examples of the aqueous emulsion (a) used in the present invention include styrene-butadiene copolymer latex, styrene-methylmethacrylate-butadiene copolymer latex, methylmethacrylate-butadiene copolymer latex, acrylonitrile-butadiene copolymer. Latex, chloroprene latex, vinylidene chloride latex, vinyl chloride emulsion, acrylic emulsion, vinyl acetate emulsion, ethylene-vinyl acetate copolymer emulsion, ethylene-vinyl chloride copolymer emulsion, ethylene-vinyl acetate-vinyl chloride copolymer emulsion, Examples thereof include natural rubber latex and urethane dispersion.

In these aqueous emulsions, the glass transition temperature (Tg)
20 to -30 ° C., solid content 40 to 65% by weight, pH 4 to 10 and further functional group-containing monomers as hydroxyl group, carboxyl group, amino group, N-methylol acid group, amide group,
An aqueous emulsion obtained by copolymerizing one or more reactive monomers having an epoxy group, an epoxide group and the like is preferable.

If the glass transition temperature (Tg) is higher than 20 ° C, it will hinder the uniform film formation of the emulsion at room temperature, causing a problem with the adhesiveness with the polyolefin. If it is lower than -30 ° C, the cohesive force will be insufficient. Adhesive strength, abrasion resistance, heat resistance, etc. become problems.

When the solid content is higher than 65% by weight, the flocking pile does not pierce the adhesive layer sufficiently because the drying is too fast, resulting in pile loss, poor abrasion resistance, flocking unevenness, etc. There is a problem in practical use because it takes time to remove water, that is, to dry, and an uneven flocking phenomenon occurs due to shrinkage of the adhesive layer accompanying water scattering.

When the pH is 10 or more, there is concern about the danger to the human body when touching the skin, and when the pH is 4 or less, there is a problem in storage stability, so-called mechanical stability when applied to an applicator, and further application. There is a problem such as rust around the machine.

Furthermore, it is indispensable to use a functional group monomer together, and mechanical stability,
It is effective in imparting adhesive strength, water resistance, moisture resistance, heat resistance and the like.

The method for producing the styrene-butadiene copolymer latex compound containing the tackifying resin (b) used in the present invention is, for example, a solution of the tackifying resin dissolved in an organic solvent, and some surfactant. A method of adding and gradually adding the styrene-butadiene copolymer latex continuously under conditions of high temperature and high speed stirring. The viscosity of the compound thus obtained is 100-10,000 cps,
The compound is preferably 500 to 3,000 cps, has a solid content of 40 to 70% by weight, preferably 50 to 60% by weight, and has a pH of 7 to 8 and excellent adhesiveness.

As the tackifying resin used in this compound,
Glycerin ester of natural or polymerized rosin, modified rosin, and hydrogenated rosin, triethylene glycol ester,
Rosin-based tackifying resin represented by pentaerythritol ester; α-pinene, β-pinene, dipentene,
Terpene resins represented by polymers such as terpene phenols; aliphatic petroleum resins; aromatic petroleum resins; alkylphenol resins; coumarone indene resins; xylene resins.

Of these, the softening point of the resin is 90-
A rosin system at 125 ° C is preferred.

As the surfactant used in producing the present compound, any of anionic and nonionic surfactants used in emulsion polymerization of ordinary emulsions can be used, but preferably has excellent emulsifying power, and Low-foaming type HLB 12 to 14 polyoxyethylene alkyl ether type can be mentioned.

As the organic solvent used in the production of this compound, basically any solvent that can dissolve the tackifying resin can be used, but from the viewpoint of the odor of the compound and the drying of the adhesive coating layer, toluene, n-hexane, n-heptane, cyclohexane, ethyl alcohol and the like,
It is desirable to use one kind or a combination of two or more kinds of these.

As the styrene-butadiene copolymer latex, a copolymerization monomer ratio of styrene and butadiene is 4/6 to 6/4, acrylic acid, methacrylic acid, itaconic acid, acrylamide, methylol acrylate, as a functional group monomer, Hydroxyethyl acrylate and hydroxyethyl methacrylate copolymerized glass transition temperature (Tg) 0 to -30 ℃, viscosity 50 to 10,000 cps, solid content 40 to 7
A latex having 0% by weight and a pH of 6 to 9 can be mentioned. The amount of functional group monomer to be copolymerized is usually 10% by weight or less of the polymer.

The mixing ratio of each is 100 parts by weight of the tackifying resin, 2 to 10 parts by weight of a surfactant, 20 to 100 parts by weight of an organic solvent, and 100 to 1,0 of a styrene-butadiene copolymer latex.
00 parts by weight is the preferred range.

Particularly preferably, the amount of the surfactant used is 4 to 6 parts by weight during the production of the compound and in view of storage stability, and the amount of the organic solvent used is 30 in view of the viscosity of the tackifying resin solution and the odor of the compound product. The amount of the styrene-butadiene copolymer latex used is preferably in the range of 300 to 600 parts by weight in view of the viscosity and the adhesive performance of the compound product.

In the present invention, the purpose of blending the compound is to improve the adhesion to polyolefin.

Concretely showing a production example of this compound, an organic solvent, a surfactant and a tackifying resin are charged in a closed pot equipped with a stirrer, and the mixture is stirred and dissolved at room temperature to 70 to 80 ° C., and the temperature after dissolution is 50%. The temperature is maintained at -60 ° C, and the styrene-butadiene copolymer latex is gradually added continuously under high-speed stirring conditions. By this method, a stable compound having an average particle size of 0.2 to 0.25μ, a solid content of 50% by weight and a pH of 8 can be obtained.

The present compound may be thickened with a water-soluble polymer, polyacrylic acid or a salt thereof, etc., if necessary.

The styrene-butadiene copolymer compound containing the tackifying resin obtained as described above has a solid content of 5 parts with respect to 100 parts by weight of the solid content of the aqueous emulsion.
To 100 parts by weight, preferably 10 to 50 parts by weight. When the amount is less than 5 parts by weight, the adhesiveness to polyolefin is not significantly improved, and when the amount is more than 100 parts by weight, the adhesive strength, heat resistance and abrasion resistance are problematic and the practicality is poor.

The chlorinated polyolefin (c) used in the present invention has a chlorine content of 12 to 35% by weight, a solid content of 19 to 63% by weight,
Viscosity 20 to 5500 cps, softening point 50 to 90 ° C (mercury method, JIS K-240
7) based on the improved method of 7).

Of these chlorinated polyolefins, a toluene-dissolved product having a chlorine content of 25 to 30% by weight, a solid content of 20 to 30% by weight, and a viscosity of 20 to 700 cps is particularly preferable in terms of workability during compounding and adhesion to polyolefin.

The chlorinated polyolefin is used in an amount of 0.1 to 10 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of the solid content of the aqueous emulsion. 0.
If the amount is less than 1 part by weight, the adhesiveness to polyolefin is not improved, and if the amount is more than 10 parts by weight, the viscosity of the adhesive composition significantly increases at the time of compounding, and at the same time, heat resistance,
The odor caused by toluene becomes more expensive, which is a practical problem.

No particular limitation is imposed on the blending of the chlorinated polyolefin, but is it blended in advance as a part of the organic solvent at the time of producing the styrene-butadiene copolymer compound containing the tackifying resin (b) described above? Alternatively, it is convenient to mix the compound in a predetermined amount after the production of the compound, as compared with the case where the compound is mixed alone, abnormal partial thickening can be alleviated.

The rosin-based aqueous emulsion type pressure-sensitive adhesive used in the present invention includes a commercially available fixed component of 40 to 60% by weight and a viscosity of 5 to 200 cp.
s, glycerin ester of rosin having a pH of 5 to 9, triethylene glycol ester, diethylene glycol ester, or an aqueous emulsion type adhesive such as pentaerythritol ester, and particularly preferred are residual tack, adhesive strength, abrasion resistance, 80 in terms of heat resistance
Examples thereof include an aqueous emulsion obtained by modifying a pentaerythritol ester of rosin having a high softening point of not less than 0 ° C., and more preferably an aqueous emulsion in which a dry coating film is colorless and transparent.

In the present invention, the blending of the rosin-based aqueous emulsion-type pressure-sensitive adhesive, in improving the adhesion to polyolefin,
The effect is remarkable.

The rosin-based aqueous emulsion-type pressure-sensitive adhesive has a solid content of the aqueous emulsion of (a) of 100 parts by weight, and the solid content is in the range of 5 to 50 parts by weight, preferably 10 to
It is in the range of 30 parts by weight.

If the amount is less than 5 parts by weight, the adhesiveness with the polyolefin will be insufficient, and if the amount is more than 50 parts by weight, uniform emulsion film formation will be impaired and the adhesive strength, abrasion resistance, water resistance, etc. will be deteriorated, which will be a problem. At the same time, the heat resistance tends to decrease, which is a practical problem.

The adhesive composition of the present invention, if necessary, a defoaming agent, a thickener,
You may add various additives, such as a thixotropic agent, an antifreezing agent, an antiaging agent, a chelating agent, a coloring agent, a drying retarder, and a crosslinking agent.

〔Example〕

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

In the following, parts and% are based on weight unless otherwise specified.

(Production Examples 1 to 6 of Aqueous Emulsion) 600 parts of pure water in 2 flasks, sodium alkylbenzene sulfonate as a surfactant [manufactured by Kao Atlas Co.,
Product name: Neoperex 05] 1 part was charged, heated to 70 ° C. with stirring under a nitrogen blanket, and then potassium persulfate 5
Parts, seed monomer (methyl methacrylate / butyl acrylate / hydroxyethyl acrylate = 10/10 /
1 mixed monomer) 5 parts and after 30 minutes of solder seed polymerization, immediately add the mixed monomer shown in Table-1 to 400 parts of pure water.
Part, Neoperex 05 5 parts preliminarily emulsified monomer was continuously administered at a uniform rate over 3 hours, and the remaining monomer treatment polymerization was similarly carried out for 3 hours to obtain the aqueous emulsion of the present invention. Next, this emulsion was mixed with 14% aqueous ammonia.
The pH was adjusted to 7.0 to obtain an emulsion having a solid content of 50% and a viscosity of 100 cps.

(Production Example 7 of styrene-butadiene copolymer latex compound containing tackifying resin) Super ester A-115 [trade name of Arakawa Chemical Industry Co., Ltd. as a rosin-based tackifying resin in a separable flask equipped with a stirrer, Softening point 110-120 ° C] 100 parts, Emulgen 910 [Kao Atlas Co., Ltd. trade name, polyoxyethylene nonylphenyl ether, HLB1 as a surfactant
2.2] 8 parts, charged with 50 parts of toluene as an organic solvent, 75
The mixture was stirred and dissolved at ℃.

Then, the solution temperature of the solution was set to 55 ° C., and 30 parts of water was gradually added under high-speed conditions, followed by styrene-butadiene copolymer latex [Mitsui Toatsu Chemical Co., Ltd., trade name Struct. Bond 1351, solid content 48%, viscosity 150cps, pH 7.0,
Glass transition temperature -30 ° C, styrene / butadiene ratio = 55/4
5, copolymer of 2 parts each of hydroxyethyl acrylate and acrylic acid] 450 parts were gradually added to form a uniform aqueous emulsion, which was then cooled to room temperature and styrene containing the tackifying resin used in the present invention. A butadiene copolymer latex compound was obtained.

This compound had a solid content of 50%, a viscosity of 1,000 cps, and a pH of 8.

(Examples 1 to 12) Aqueous emulsion having the number of parts shown in Table 2 (Production Examples 1 to 1)
6), a styrene-butadiene copolymer latex compound containing a tackifying resin (Production Example 7), a chlorinated polyolefin [manufactured by Sanyo Kokusaku Pulp Co., Ltd., trade name: Supercron 82L, chlorine content 27%, solid content 30%, viscosity 60c
ps], rosin-based aqueous emulsion type adhesive [manufactured by Arakawa Chemical Industry Co., Ltd., trade name Super Ester E720, solid content 50%,
pH 7, viscosity 100 cps, softening point 100 ° C.] were sequentially mixed with stirring to obtain an adhesive composition of the present invention.

The viscosity of the adhesive composition was adjusted to 3000 cps by using an aqueous solution of hydroxyethyl cellulose as a thickener.

Adhesive compositions obtained as described above (Examples 1 to 12)
Was evaluated by the following method, and the results are shown in Table 3.

(1) Electrostatic flocking processing A polyethylene film having a pressure of 100 µm is uniformly coated with 200 g / m ² of the adhesive composition of the present invention by using air spray.
Then, a nylon pile having a denier of 3 mm and a length of 0.5 mm was flocked by applying a voltage of 30 KV with an electrostatic flocking machine and dried with a hot air dryer at 60 ° C. for 60 minutes to prepare a flocked sample for evaluation.

(2) Evaluation method (a) Adhesion Adhesive was applied to a polyethylene film by the same method as the application method of (1) electrostatic flocking, and immediately cotton broad ^#
40 pieces of cloth are stuck together, dried for 60 minutes in a hot air dryer at 60 ° C., cooled to room temperature, and the peeled state is observed with a fingertip, and the adhesion to the polyethylene film is displayed as shown below.

○: Adhesive remains on the polyethylene film interface.

Δ: There is peeling resistance although peeling from the polyethylene film interface.

×: Easy peeling from the polyethylene film interface (b) Adhesive strength (a) The adhesive sample was cut into a width of 25 mm and a length of 100 mm,
Using a Tensilon tensile tester, peeling was performed in the direction of an angle of 180 ° at a speed of 200 mm / min, and the adhesive strength was displayed in Kg / 25 mm.

(C) Heat resistance According to the above (b) adhesive strength, the adhesive strength was measured in a constant temperature bath at 60 ° C, and the heat resistance was expressed in Kg / 25 mm.

(D) Abrasion resistance Using a Gakushin type friction fastness tester, cotton broad ^#
Attach 40 cloths, load at 500g, 30 times / min at a speed of 30
The flocked surface of × 200 mm was rubbed, and the presence or absence of abnormality of the flocked surface after rubbing 3,000 times was displayed as follows.

○: No abnormality △: Partial thinning of hair ×: More than half of hair loss per area (e) Water resistance A hair transplant sample was immersed in room temperature water for 10 minutes, and tested in accordance with the above-mentioned (d) abrasion resistance test method. The presence or absence of abnormality on the flocked surface after 500 rubs was displayed as follows.

A: No abnormality O: Hair loss is 1-5% per area B: Hair loss is 5-20% per area X: Hair loss is 20% or more per area (Comparative Example 1) Obtained in Production Example 1 used in Example 1. Only the aqueous emulsion was thickened with an aqueous solution of hydroxyethyl cellulose and subjected to the same evaluations as in Example 1, and the results are shown in Table-3.

(Comparative Example 2) Only the compound obtained in Production Example 7 used in Example 1 was thickened with an aqueous solution of hydroxyethyl cellulose, subjected to the same evaluations as in Example 1, and the results are shown in Table-3.

(Comparative Example 3) Only the aqueous emulsions obtained in Comparative Examples 1 and 2 and the compound were mixed in the same proportion as in Example 1 and subjected to the same evaluation as in Example 1, and the results are shown in Table 3. .

(Comparative Example 4) The adhesive composition obtained by removing the (d) rosin-based aqueous emulsion type pressure-sensitive adhesive from Example 1 was blended and subjected to the same evaluations as in Example 1, and the results are shown in Table-3.

(Comparative Example 5) The adhesive composition obtained by removing (c) the chlorinated polyolefin from Example 1 was blended and subjected to the same evaluation as in Example 1, and the results are shown in Table 3.

As is clear from Table 3, in Comparative Example 1 containing only the aqueous emulsion, adhesion, abrasion resistance, and water resistance were poor,
Both adhesive strength and heat resistance are low. Also in Comparative Example 2 containing only the compound, the abrasion resistance was poor, the adhesion was not good, and the adhesive strength and heat resistance were low. Also in Comparative Example 3 in which only the aqueous emulsion and the compound were used, adhesion, abrasion resistance,
The water resistance is not good, and the adhesive strength and heat resistance are less than half that of the examples.

In Comparative Example 4 containing no rosin-based aqueous emulsion,
It is much better than the other comparative examples, but the adhesiveness and wear resistance are not so good, and the adhesive strength and heat resistance are considerably lower than those of the examples.

Even in Comparative Example 5 containing no chlorinated polyolefin, the adhesive strength and heat resistance are lower than in Comparative Example 4, and the water resistance is not good.

On the other hand, those of Examples 1 to 12 are not good in some characteristic values, but generally have good adhesion, abrasion resistance and water resistance, and have high adhesive strength and heat resistance. .

〔The invention's effect〕

Although the adhesive composition of the present invention uses a small amount of an organic solvent in the step of emulsifying the tackifying resin, the chlorinated polyolefin, and the rosin-based adhesive, it is generally an aqueous emulsion type adhesive. Yes, compared to solvent-based adhesives, the amount of organic solvent is extremely small, and there is no concern about environmental pollution due to organic solvents, fire hazard, occupational hygiene problems, etc. It has excellent adhesion, adhesive strength, heat resistance, etc. to the film or foam.

When this adhesive composition is used for electrostatic flocking on a polyolefin substrate, there is no uneven flocking as experienced with solvent-based adhesives, and piles on the adhesive layer as seen in hot melt adhesives. Not only there is no piercing defect, but it is possible to apply evenly with any application method such as air spray, roll coater, flow coater that is usually used for adhesive application for electrostatic flocking, adhesion with polyolefin,
Since it is an adhesive for electrostatic flocking that has excellent adhesive strength, heat resistance, abrasion resistance, water resistance, and even flocking unevenness, its practical value is extremely high and its significance is great.

Claims (6)

[Claims] 1. An aqueous emulsion (a) having a solid content of 100
On the basis of parts by weight, (b) a styrene-butadiene copolymer latex compound containing a tackifying resin as solid content of 5 to 5 parts by weight.
100 parts by weight, (c) 0.1 to 10 parts by weight of chlorinated polyolefin as a solid content, (d) 5 to 50 parts by weight of rosin-based aqueous emulsion adhesive as a solid content, (a) (b) (c) above An adhesive composition for electrostatic flocking of a polyolefin substrate, which comprises (d). 2. The glass transition temperature (T
g) 20 to -30 ° C, solid content 40 to 65% by weight, pH 4 to 10
The adhesive composition for electrostatic flocking of a polyolefin substrate according to claim 1, wherein the reactive monomer having a functional group is copolymerized with one kind or two or more kinds. 3. A styrene-butadiene copolymer latex compound containing a tackifying resin, having a glass transition temperature (Tg) of 0 to -30 ° C., a viscosity of 50 to 10,000 cps, and a solid content of 4
The adhesive composition for electrostatic flocking of a polyolefin substrate according to claim 1, which is a latex compound having a pH of 6 to 9 and a weight ratio of 0 to 70%. 4. A styrene-butadiene copolymer latex compound according to claim 3, 100 parts by weight of a tackifying resin, 2 to 10 parts by weight of a surfactant, and 20 parts of an organic solvent.
To 100 parts by weight and 100 to 1000 parts by weight of a styrene-butadiene copolymer latex are emulsified, and the adhesive composition for electrostatic flocking of a polyolefin substrate according to claim 1, characterized in that Stuff. 5. The chlorinated polyolefin has a chlorine content of 12 to 35.
The polyolefin group according to claim 1, which is an organic solvent solution having a weight%, a solid content of 19 to 63% by weight, a viscosity of 20 to 5500 cps, and a softening point of 50 to 90 ° C. (mercury method, JIS K-2407 improved method). Adhesive composition for electrostatic flocking of wood. 6. A rosin-based aqueous emulsion-type pressure-sensitive adhesive selected from glycerol glycerol ester, triethylene glycol ester, diethylene glycol ester or pentaerythritol ester having a solid content of 40 to 60% by weight, a viscosity of 5 to 200 cps and a pH of 5 to 9. The adhesive composition for electrostatic flocking of a polyolefin-based material according to claim 1, which is one or two or more aqueous emulsion type pressure-sensitive adhesives.