JP5180464B2 - Emulsion precursor and emulsion - Google Patents

Description

The present invention relates to an emulsion precursor using a thermoplastic resin and an emulsion containing the emulsion precursor and water.

A so-called emulsion obtained by emulsifying resin particles in a liquid using a surfactant as a dispersant is widely used in the production of pressure-sensitive adhesives for pressure-sensitive adhesive tapes and pressure-sensitive adhesive sheets.
The resin particles in the emulsion are thermodynamically unstable because they are dispersed by the electrostatic repulsion of the electric double layer due to the surfactant, and if van der Waals attraction greater than the repulsion acts, the particles Agglomerates. Aggregated particles settle or float in the emulsion and phase separate, making it difficult to store for a long time.

A general emulsion has a dispersion medium such as 50% or more of water in addition to the resin particles, and this dispersion medium is removed during the product processing. That is, when the emulsion is transported, a dispersion medium unnecessary for the final product must be transported, which greatly affects the cost of the final product.

For this reason, when using the emulsion, it is desirable to make the thermoplastic resin into an emulsion immediately before the place of use. However, in order to obtain an emulsion of the thermoplastic resin, as described later, a large-scale is required. It was not realistic because it required equipment and a lot of power.

Specifically, as a method for obtaining an emulsion of a thermoplastic resin, a high pressure emulsification method, a phase inversion emulsification method, a D phase emulsification method, an ultrasonic emulsification method, a membrane emulsification method, and the like are known. There is known a mechanical emulsification method or the like in which fine particles are formed by using a magnetic field.

Thermoplastic resins are solid or semi-solid at room temperature, so mechanical emulsification requires a large amount of power for stirring and the like, and is restricted by resin viscosity in terms of equipment during emulsification. In order to remove the restriction of the viscosity, a method of lowering the viscosity of the thermoplastic resin by dissolving the resin in an organic solvent and recovering the organic solvent by vacuum distillation after emulsification is used. However, it has been difficult to completely remove the organic solvent from the emulsion obtained by this method.

In addition, development of solvent-free emulsions has been studied from the viewpoint of environmental response in recent years. For example, a method of lowering the viscosity of a thermoplastic resin by a phase inversion emulsification method in a high temperature and high pressure environment is known (for example, Patent Documents 1 to 3).

As another means for lowering the viscosity of the thermoplastic resin, emulsification by an extruder capable of kneading at a higher torque than that of a stirrer is also performed (for example, Patent Documents 4 to 5). This method is a method in which the viscosity of the thermoplastic resin is lowered by the shearing force of the screw of the extruder to obtain an emulsion, but the obtained emulsion is inferior in storage stability. This is because the average particle diameter of the resin particles of the emulsion obtained by this method exceeds 1 μm, and oil-water separation is likely to occur in a short time. Therefore, in order to improve the storage stability of the emulsion, it is necessary to reduce the particle size of the resin particles of the emulsion.

JP-A-11-209477 JP-A-7-155576 JP 2004-290800 A JP-A 56-2149 JP-A-4-20532

It is an object of the present invention to provide an emulsion precursor having good storage stability, which can be made into an emulsion without requiring special equipment, and an emulsion composed of the emulsion precursor and water.

That is, the present invention is an emulsification precursor containing 100 parts by mass of a thermoplastic resin, 1 to 20 parts by mass of a surfactant, and 0.1 to 30 parts by mass of water. The emulsion precursor is preferably obtained by kneading these materials with a kneading apparatus. The thermoplastic resin is preferably at least one selected from vinyl polymers, diene polymers, and ether polymers, and the vinyl polymer is preferably at least one selected from petroleum resins, rosin resins, and terpene resins. The surfactant is preferably at least one selected from an anionic surfactant, a cationic surfactant, a nonionic surfactant, and an amphoteric surfactant.
Another invention of the present application is an emulsion obtained by mixing 100 parts by mass of an emulsion precursor and 40 to 10,000 parts by mass of water. The emulsion can be used as a pressure-sensitive adhesive or adhesive, and these can be used as materials for pressure-sensitive adhesive tapes, pressure-sensitive adhesive sheets, and pressure-sensitive adhesive films.

An emulsion precursor having good storage stability and an emulsion composed of the emulsion precursor and water can be obtained without requiring special equipment. The emulsification precursor is a solid in which a surfactant and water are uniformly dispersed in a thermoplastic resin, and can be made into an emulsion simply by adding it to water at room temperature. For this reason, it is possible to reduce the cost of the final product because there is no phase separation as in the case of conventional emulsions and it is not necessary to transport an unnecessary dispersion medium to the final product.

Thermoplastic resins include polyolefin resins, polystyrene resins, acrylic resins, acrylonitrile resins, halogen resins, fluororesins, petroleum resins, rosin resins, terpene resins, alkyl resins, xylene resins, coumarone resins, coumarone indene resins, and other vinyl heavy resins. Examples of the polymer include diene polymers such as isoprene resins and butadiene resins, ether polymers, and silicon polymers, polyurethane, polyisoprene, butadiene, and the like.

Specific examples of the vinyl polymer include polyethylene, polypropylene, polyisobutylene, ethylene-propylene copolymer, ethylene-acrylic acid copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl acetate-acrylic as polyolefin resin. As an acrylic resin such as polystyrene, acrylonitrile-butadiene-styrene copolymer, methyl methacrylate-butadiene-styrene copolymer, methyl methacrylate-styrene copolymer, styrene-butadiene copolymer, etc. Polyacrylonitrile, acrylonitrile-styrene copolymer, acrylonitrile-butadiene polymer as acrylonitrile resin such as polymethyl methacrylate, poly-2-ethylhexyl acrylate, etc. There is.
Further, as a halogen resin, polyvinyl chloride, polyvinylidene chloride, polychloroprene, etc., as a fluororesin, polytetrafluoroethylene, polyvinylidene fluoride, etc., as a petroleum resin, a C5 fraction petroleum resin, a C9 fraction As terpene resins such as rosin resin, rosin ester resin, rosin phenol resin, etc., rosin resin, C5 / C9 fraction petroleum resin, DCPD petroleum resin, styrene petroleum resin, hydrogenated petroleum resin, etc. , Α-pinene resin, β-pinene resin, terpene phenol resin, alkylphenol resin as alkyl resin, and the like.

Specific examples of the diene polymer include polyisoprene as an isoprene resin, acrylonitrile-butadiene copolymer and styrene-butadiene copolymer as a butadiene resin. Specific examples of the ether polymer include polyoxymethylene, polyoxyethylene, and polydimethylsiloxane.

Among these thermoplastic resins, preferred are polyolefin resins that are vinyl polymers, styrene-butadiene polymers, isoprene polymers, and butadiene polymers that are polystyrene resins and diene polymers. Resin, rosin resin, terpene resin such as C5 fraction petroleum resin, C9 fraction petroleum resin, C5 / C9 fraction petroleum resin, DCPD petroleum resin, styrene petroleum resin, rosin acid ester resin, polymerization Use of a rosin resin, α-pinene resin, β-pinene resin, or terpene phenol resin is preferable because an emulsion having improved storage stability can be obtained.
These thermoplastic resins may be used alone or in combination of two or more.

The surfactant is not particularly limited, and is an anionic surfactant, a cationic surfactant, a nonionic surfactant, an amphoteric surfactant, or a polymer that is used in normal emulsification processing. A variety of surfactants, fluorine surfactants, reactive surfactants, and the like can be used. These surfactants may be used alone or in combination.

Among these surfactants, it is preferable to use an anionic surfactant since the emulsion precursor is easily emulsified. Examples of the anionic surfactant include fatty acid type, alkylbenzene type, sulfate ester type, higher alcohol type and the like, for example, higher fatty acid sodium, sodium alkylsulfonate, sodium alkylbenzenesulfonate, sodium alkyldiphenyl ether disulfonate, etc. .

The addition amount of the surfactant is 1 to 20 parts by mass, preferably 3 to 10 parts by mass with respect to 100 parts by mass of the thermoplastic resin. If the surfactant is less than 1 part by mass, the stability of the emulsion is poor, and if it exceeds 20 parts by mass, the water resistance of the resulting pressure-sensitive adhesive or adhesive decreases or the cost increases.

Water is not particularly limited, but pure water such as distilled water or ion exchange water is preferably used.
The amount of water added is 0.1 to 30 parts by mass, preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the thermoplastic resin. If it is less than 0.1 part by mass, an emulsion having good stability cannot be obtained when the obtained emulsion precursor is mixed with water, and if it exceeds 30 parts by mass, it is difficult to uniformly disperse it in the thermoplastic resin.

It is desirable that the surfactant and water are uniformly dispersed in the thermoplastic resin. The means for uniformly dispersing the surfactant and water in the thermoplastic resin is not particularly limited. For example, after mixing these with a blender such as a Henschel mixer, the single screw extruder or twin screw extruder is mixed. What is necessary is just to knead | mix using a machine, a kneader, a Banbury mixer, a kneading roll, etc. The kneading apparatus preferably uses equipment that does not evaporate water during kneading, or is kneaded by setting the kneading conditions to 100 ° C. or lower. In the kneading step, a desired stabilizer, antioxidant, weathering agent, ultraviolet absorber, lubricant, pigment, dye, crosslinking agent, filler, plasticizer, crosslinking accelerator, etc. may be added to the emulsion precursor. I can do it.

In the kneading step, a plasticizer may be added to facilitate the kneading of the thermoplastic resin. As a plasticizer, a compound that gives a plasticizing effect to a thermoplastic resin, for example, phthalate ester, adipic ester, phosphoric ester, trimellitic ester, citrate ester, epoxy, polyester Etc.

When the plasticizer is added in an amount of 40 parts by mass or less, preferably 10 parts by mass or less, more preferably 5 parts by mass or less, with respect to 100 parts by mass of the thermoplastic resin, the properties of the resulting thermoplastic resin are not inhibited. Therefore, it is preferable.

The shape of the emulsion precursor is not particularly limited, and examples thereof include powder, granule, pellet, sheet, and film. Among these, the powder form is preferable because the emulsification time when the thermoplastic resin is used as an emulsion is shortened.

The emulsification precursor can be made into an emulsified product simply by being put into water and left standing, and the emulsification time can be shortened by stirring after being put into water. A known mixing device can be used as the mixing and stirring device, and is not particularly limited, but a magnetic stirrer, three-one motor, homogenizer, media mill, colloid mill, homomixer, planetary mixer, in-line mixer, pipeline mixer, etc. is there.

Each temperature of an emulsification precursor and water is not particularly limited, and can be arbitrarily changed according to the purpose of use.

In order to dissolve the emulsion precursor, various additives can be added to water as long as the effects of the present invention are not impaired. Examples of various additives include antiseptics, antifungal agents, permeability adjusters, pH adjusters, and other emulsions.

The obtained emulsion can be used for various applications as it is, but if necessary, an antifoaming agent, an antiseptic, an antifungal agent, an antirust agent, a permeability adjusting agent, a viscosity viscosity adjusting agent, a pH adjusting agent. Various additives and other emulsions such as an agent, a flame retardant, a dispersant, an inorganic filler, an aggregate such as silica sand, and a pigment can be added. Further, a water-soluble polymer such as hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, a conventionally known anionic, cationic or nonionic surfactant may be added.

The emulsion can be used as a pressure-sensitive adhesive or an adhesive by mixing with rubber latex obtained by itself or by emulsion polymerization, other emulsions, additives and the like.

Various other additives are contained in the pressure-sensitive adhesive and the adhesive as necessary. Such additives are not particularly limited, for example, antifoaming agents, antiseptics, antifungal agents, rust inhibitors, permeability adjusters, viscosity viscosity adjusters, antiaging thickeners, flame retardants, dispersions Agents, inorganic fillers, aggregates such as silica sand, and pigments. Further, if necessary, a water-soluble polymer such as hydroxyethyl cellulose, methyl cellulose, or carboxymethyl cellulose, a conventionally known anionic, cationic or nonionic surfactant may be used.

Adhesives and adhesives are suitable for bonding of the same or different types of paper, wood, cloth, leather, jersey, leather, rubber, plastic, foam, earthenware, glass, mortar, cement material, ceramic, metal, etc. is there. With respect to the construction method at the time of bonding, brush coating, trowel coating, spray coating, roll coater coating and the like are possible.

An adhesive tape, an adhesive sheet, an adhesive film, etc. can be obtained by applying the obtained adhesive to a support and drying it.

The support is, for example, a plastic sheet and foam such as polypropylene resin, polyethylene resin, polystyrene resin, vinyl chloride resin, Japanese paper, kraft paper, coated paper, fine paper, synthetic paper, cloth, nonwoven fabric, etc. Examples thereof include porous substances, composites thereof, and multilayer laminates.

The surface of the support can be coated with a primer or corona treated. Moreover, in order to adjust the adhesive strength of the pressure-sensitive adhesive composition, a release agent can be applied to the pressure-sensitive adhesive application back surface.

The pressure-sensitive adhesive tape, pressure-sensitive adhesive sheet, and pressure-sensitive adhesive film are completed by applying a pressure-sensitive adhesive to the support, drying it, and cutting it into predetermined dimensions. Examples of the method for applying the adhesive to the support include a direct gravure method, a reverse direct gravure method, an offset gravure method, a knife coater, a roll coater, a comma coater, a lip coater, and a die coater. Also, the primer and release agent can be applied in the same manner.

The thickness of the pressure-sensitive adhesive layer is not particularly limited. For example, when the thickness is in the range of 1 to 100 μm, preferably 10 to 50 μm, the necessary adhesive force is exhibited, and the coating performance and drying properties are improved. Therefore, it is preferable.

（式中、Ｎは不揮発分（％）、ｍ_０は平底皿の質量（ｇ）、ｍ_１は平底皿と試料との合計質量（ｇ）、ｍ_２は平底皿と蒸発残留分との合計の質量（ｇ）を表す。）
［平均粒子径］
乱式粒度分布測定装置 ＬＡ-９２０（ 株式会社堀場製作所社製）を用いレーザー回折法でメジアン径測定を実施した。評価は、平均粒子径と安定性の関係を考慮し、０．５μｍ以下のものを優、０．５〜１．０μｍのものを良、１．０μｍ以上のものを不可とした。
[貯蔵安定性]
熱可塑性樹脂乳化物をガラス瓶に入れて密栓し、４０℃のオーブン中で４週間貯蔵し、貯蔵安定性評価を実施した。評価は、層分離が無くかつ平均粒子径の変化が無いものを優、層分離は無いが平均粒子径の変化があったものを良、層分離したものを不可とした。 [Example 1]
Petroleum resin (softening point 85 ° C., trade name U-185; manufactured by Zeon Corporation) and alkyl diphenyl ether disulfonate (trade name Plex SS-H; manufactured by Kao Corporation anionic surfactant) component 5.0 parts And 5.0 parts of water were kneaded at 100 rpm with a twin-screw melt extruder (TEX-30α; manufactured by Nippon Steel) at 90 ° C., and then the kneaded material discharged from the die was air-cooled to form a strand shape An emulsion precursor was obtained. The water content of the composition was measured with a Karl Fischer moisture meter (MKC-210; Kyoto Electronics), and the amount of water blended was calculated. The collected strand was pulverized into pellets and mixed with 100 parts of distilled water to obtain an emulsion, and the characteristics were examined by the following method.
[Emulsifying]
A white emulsion can be obtained by adding 100 parts of the pellet-like emulsified precursor to 100 parts of distilled water at 25 ° C. and allowing to stand for 1 hour. The nonvolatile content of the emulsion was calculated according to JIS K6828-1. The measurement was performed according to the following procedure. Weigh 1.0 g of the emulsion that does not contain the insolubles of the emulsion precursor into a flat bottom dish and dry it in an oven at 105 ° C (ACR gear oven; manufactured by Toyo Seiki Seisakusho) for 1 hour. , Calculated by the general formula (Equation 1). In the evaluation, those having a nonvolatile content of 45% or more were excellent, those having a nonvolatile content of 15% or more and less than 45% were good, and those having a nonvolatile content of less than 15% were not acceptable.

(Where N is the non-volatile content (%), m ₀ is the mass (g) of the flat bottom pan, m ₁ is the total mass (g) of the flat bottom pan and the sample, and m ₂ is the sum of the flat bottom pan and the evaporation residue. Represents the mass (g) of
[Average particle size]
The median diameter was measured by a laser diffraction method using a random particle size distribution analyzer LA-920 (manufactured by Horiba, Ltd.). In consideration of the relationship between the average particle size and the stability, the particles having a size of 0.5 μm or less were excellent, those having a particle size of 0.5 to 1.0 μm were good, and those having a particle size of 1.0 μm or more were not acceptable.
[Storage stability]
The thermoplastic resin emulsion was put in a glass bottle, sealed, and stored in an oven at 40 ° C. for 4 weeks to evaluate the storage stability. The evaluation was excellent when there was no layer separation and there was no change in the average particle size, and when there was no layer separation but there was a change in the average particle size, it was good.

[Example 2]
The test was carried out in the same manner as in Example 1 except that the surfactant used in Example 1 was changed to dodecylbenzenesulfonate (trade name Neoperex G-65; an anionic surfactant manufactured by Kao Corporation). Example 2 was adopted.

[Example 3]
A test was carried out in the same manner as in Example 1 except that the surfactant used in Example 1 was changed to a nonionic surfactant (trade name: Emulgen 123P; manufactured by Kao Corporation).

[Example 4]
A test was carried out in the same manner as in Example 1 except that the surfactant used in Example 1 was changed to a cationic surfactant (trade name Cotamine 24P; manufactured by Kao Corporation).

[Examples 5 to 6]
Except having changed the blending quantity of distilled water of Example 1 into 5 parts, the test was implemented similarly to Example 1 and it was set as Examples 5-6.

[Examples 7 to 8]
Except having changed the surfactant amount of Example 1 to 10 parts, the test was carried out in the same manner as in Example 1 to obtain Examples 7 to 8.

[Example 9]
A test was conducted in the same manner as in Example 1 except that the thermoplastic resin used in Example 1 was changed to a petroleum resin having a softening point of 95 ° C. (trade name Escoretz 2101; manufactured by ExxonMobil Co., Ltd.).

[Example 10]
A test was carried out in the same manner as in Example 1 except that the thermoplastic resin used in Example 1 was changed to a petroleum resin having a softening point of 115 ° C. (trade name G-115; manufactured by Nippon Zeon Co., Ltd.). .

[Example 11]
The test was carried out in the same manner as in Example 1 except that the thermoplastic resin used in Example 1 was changed to a hydrogenated petroleum resin (softening point 100 ° C., trade name P-100; manufactured by Arakawa Chemical Industries). Example 11 was used.

[Example 12]
A test was carried out in the same manner as in Example 1 except that the thermoplastic resin used in Example 1 was changed to a terpene resin (softening point 100 ° C., trade name PX-1000; manufactured by Yasuhara Chemical Co., Ltd.). .

[Example 13]
A test was carried out in the same manner as in Example 1 except that the thermoplastic resin used in Example 1 was changed to a styrene-butadiene copolymer (trade name JSR1502; manufactured by JSR Corporation).

[Example 14]
A test was carried out in the same manner as in Example 1 except that the thermoplastic resin used in Example 1 was changed to a natural rubber pale crepe (produced in Malaysia) which is an elastomer.

[Example 15]
Example 1 except that the thermoplastic resin used in Example 1 was changed to polystyrene (trade name G100C; Toyo Styrene) and 20 parts of a plasticizer, diisononyl phthalate (DINP; manufactured by Jay Plus) was added. A test was conducted in the same manner as Example 15.

[Example 16]
Example 1 except that the thermoplastic resin used in Example 1 was changed to polyethylene (trade name Novatec LL; Nippon Polyethylene) and 20 parts of a plasticizer diisononyl phthalate (DINP; manufactured by Jay Plus) was added. The test was conducted in the same manner as in Example 16.

[Comparative Examples 1-2]
Except having changed the blending quantity of distilled water of Example 1 into the quantity shown in Table 3, the test was implemented like Example 1 and it was set as Comparative Examples 1-2.

[Comparative Examples 3 to 4]
A test was carried out in the same manner as in Example 1 except that the amount of the surfactant in Example 1 was changed to the amount shown in Table 3, and Comparative Examples 3 to 4 were made.

As can be seen from Tables 1 to 3, the emulsion precursor of the present invention can obtain an emulsion without requiring special equipment, and is excellent in both the average particle size and storage stability of the obtained emulsion. .

In Tables 1 to 3, details of the thermoplastic resin are shown in Table 4, and details of the surfactant are shown in Table 5, respectively.

Even after the thermoplastic resin obtained by the present invention is stored at room temperature for 3 months, it can be made into an emulsion by mixing with 100 parts of distilled water in the same manner as the original one. The obtained emulsion also showed various physical properties similar to those at the time of preparation.

The emulsion precursor of the present invention can obtain an emulsion having good stability only by being dissolved in water, and can reduce the cost for emulsification equipment and transportation.

Claims (1)

100 parts by mass of at least one vinyl polymer or ether polymer selected from petroleum resin, rosin resin, terpene resin , anionic surfactant, cationic surfactant, nonionic surfactant, amphoteric interface An emulsification precursor obtained by kneading 1 to 20 parts by mass of a surfactant selected from activators and 0.1 to 1.5 parts by mass of water using a kneader.