JP2008038057A - Rubber component-containing aqueous dispersion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an adhesive having improved workability, excellent adhesive strength and cohesive power and good flexibility. <P>SOLUTION: The water dispersion containing a rubber component is obtained by dispersing a rubber component-containing composition comprising a rubber component (A) selected from a diene copolymer and an ethylene-α-olefin copolymer, a tackifier resin (B) and a plasticizer (C) into water by a polymeric emulsifying agent. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rubber component-containing aqueous dispersion used for hot melt bonding. More specifically, the present invention relates to an aqueous dispersion containing a rubber component for hot-melt bonding that is particularly suitable for bonding polyolefin-based resin molded articles.

  As hot-melt adhesives used for bonding polyolefin films, nonwoven fabrics, resin molded products, etc., styrene-ethylene-propylene-styrene block copolymer rubber and styrene-butadiene-styrene block copolymer rubber are generally used. In addition, liquid plasticizers such as tackifying resin components and process oil, and other additives are known (see, for example, Patent Documents 1 to 3).

  By the way, a hot melt adhesive is produced by homogenizing two or more kinds of rubber components, tackifiers, plasticizers, other additives, and the like by melting them at high temperature. However, since the melt viscosity is from several thousand to several tens of thousands mPa · s, the fluidity is low and the mixing property is poor. Oxidation degradation due to the above, etc., and performance could not be fully exhibited. Moreover, since it has high viscosity, it is difficult to apply a small amount, and it may be thickly applied, which may be disadvantageous economically.

  In order to improve this point, a method for reducing the viscosity and improving workability by using a large amount of a plasticizer or a resin having a reduced molecular weight was studied. However, these additions may cause problems such as a decrease in cohesion and holding power, and a decrease in adhesion to the adherend.

  In addition, organic solvents are sometimes used to maintain performance, but there are problems such as environmental problems and danger of explosion.

  In order to solve such problems as the environmental problem and the danger of explosion, water-dispersed hot melt adhesives have been studied. As a production method, a method is known in which hot melt resin is freeze-pulverized and crushed particles of several tens of μm to several hundreds of μm are dispersed in water (see, for example, Patent Document 4).

JP-A-8-60121 Japanese Patent No. 3038549 JP 2005-105205 A JP 2001-214146 A

  However, the method described in Patent Document 4 described above requires a freeze pulverization step and a sieving step, and a large amount of dust is generated, resulting in poor workability.

  Therefore, the present inventors have aimed to solve these problems, improve workability, obtain an adhesive having excellent adhesive force and cohesive force, and good flexibility.

  The present invention provides a rubber component-containing composition containing a rubber component (A) selected from a diene copolymer and an ethylene-α-olefin copolymer, a tackifier resin (B), and a plasticizer (C). The above problem was solved by dispersing in water with a molecular emulsifier.

  Since the rubber component-containing aqueous dispersion according to the present invention is an emulsion using water as a medium, the viscosity is low, the flexibility is good, and workability such as coating can be improved. In addition, safety is increased because no organic solvent is used. Furthermore, since it is not necessary to heat for a long time at the time of bonding, there is no problem of thermal degradation, and sufficient adhesive force and cohesive force can be exhibited.

Hereinafter, the present invention will be described in detail.
In the rubber component-containing aqueous dispersion according to the present invention, a rubber component-containing composition containing a rubber component (A), a tackifier resin (B), and a plasticizer (C) is dispersed in water with a polymer emulsifier. It is a dispersion.

<Rubber component (A)>
The rubber component (A) refers to a rubber component selected from a diene copolymer and an ethylene-α-olefin copolymer. In this specification, “(co) polymer” means “homopolymer or copolymer”.

  The diene copolymer is a monomer comprising a diene having 4 to 18 carbon atoms, or a monomer comprising a diene having 4 to 18 carbon atoms and another monomer as a structural unit. , And its hydride. Examples of the monomer having 4 to 18 carbon atoms include butadiene and isoprene, and other monomers include aromatic vinyl monomers, olefins, unsaturated nitriles, and the like. can give.

  The aromatic vinyl monomer is preferably an aromatic vinyl monomer having 8 to 20 carbon atoms such as α-methylstyrene and styrene. Moreover, as said olefin, a C2-C8 olefin is preferable, for example, ethylene, propylene, etc. are mention | raise | lifted. Furthermore, as an unsaturated nitrile, a C4-C16 unsaturated nitrile is preferable, for example, an acrylonitrile etc. are mention | raise | lifted.

  When obtaining the copolymer of the said diene and another monomer, these compounding ratios are diene / other monomer, and 0.1 / 99.9 or more and 10/90 or less are preferable.

  Specific examples of such a diene copolymer include butadiene rubber, isoprene rubber, natural rubber, butyl rubber, nitrile rubber, styrene-butadiene block copolymer rubber (SBS), and styrene-isoprene block copolymer rubber (SIS). Styrene-butadiene random copolymer rubber (SBR), hydrides in which some or all of the diene units of these diene copolymers are hydrogenated, and the like.

  Examples of the hydride in which some or all of the diene units of the diene copolymer are hydrogenated include styrene- (ethylene-propylene) block copolymer rubber (SEPS; SIS hydride), styrene- (ethylene-butene). ) Block copolymer rubber (SEBS; hydride of SBS), hydrogenated SBR, and the like.

  Examples of the ethylene-α-olefin copolymer include a copolymer rubber of ethylene and α-olefin, and a terpolymer rubber of ethylene, α-olefin and non-conjugated diene.

  The α-olefin used for the copolymer rubber of ethylene and α-olefin is preferably an α-olefin having 3 to 18 carbon atoms, such as propylene, 1-butene, 1-pentene, 4-methyl-1-pentene. Etc.

  The blending ratio (weight ratio) of ethylene and α-olefin in the copolymer rubber is preferably 0.1 / 99.9 or more and preferably 10/90 or more in terms of ethylene / α-olefin. If it is smaller than 0.1 / 99.9, the cohesive force is lowered, and it may be difficult to use as an adhesive. On the other hand, the upper limit of the blending ratio is preferably 95/5, and preferably 90/10. When it is larger than 95/5, the cohesive force is lowered, and it may be difficult to use as an adhesive.

  The non-conjugated diene used in the terpolymer rubber of ethylene, α-olefin and non-conjugated diene is preferably a non-conjugated diene having 4 to 18 carbon atoms, such as ethylidene norbornene, 5-ethylidene-2-norbornene, diene. Examples thereof include cyclopentadiene and 1,4-hexadiene. Examples of the α-olefin used in the terpolymer rubber include the above-mentioned α-olefins.

  And the compounding ratio (weight ratio) of the said terpolymer rubber is 30: 90: 5-69.9: 0.1-30 with ethylene: alpha-olefin: nonconjugated diene, and 30-80: 5 is good. ~ 60: 0.1-20 is preferred. When there is too little ethylene, there exists a tendency for the cohesive force at the time of adhesion | attachment to become inadequate. On the other hand, when there is too much ethylene, crystallinity will become high and there exists a possibility that adhesive force may be insufficient. Moreover, when there are too few alpha olefins, there exists a tendency for the cohesion force at the time of adhesion | attachment to become inadequate. On the other hand, if the α-olefin is too much, the glass transition temperature is high and the polymer becomes a hard polymer, and the adhesive strength tends to be insufficient. Furthermore, when there are too few nonconjugated dienes, there exists a possibility that elasticity and flexibility may fall and adhesive force may be insufficient. On the other hand, when there are too many non-conjugated dienes, a crosslinked structure is generated and hardened, and adhesion failure tends to occur.

  Among the rubber components (A), preferred are diene copolymers and hydrides thereof, and particularly preferred are SBS, SIS, SEPS, and SEBS, or a mixture of two or more thereof. .

  The number average molecular weight of the rubber component (A) is preferably 10,000 to 400,000, more preferably 30,000 to 300,000. By setting the number average molecular weight of the rubber component (A) within the above range, a hot melt adhesive having a good balance between cohesive force and melt viscosity can be obtained. Cohesive force is a factor affecting adhesive strength, and melt viscosity is a factor affecting adhesive processability.

  The melt index (MFI) of the rubber component (A) according to the ASTM D1238-G method (200 ° C., 5,000 g) is preferably 300 cm / 10 min or less, more preferably 100 cm / 10 min or less. By setting the melt index (MFI) of the rubber component (A) within the above range, a hot melt adhesive having a good balance between cohesive force and melt viscosity can be obtained.

  The rubber component (A) of the present invention has the above-mentioned composition, and can exhibit hot melt adhesive performance rich in flexibility by including two kinds of a linear rubber component and a radial rubber component. it can.

  The linear rubber component refers to a rubber component in which molecular chains are not branched and so-called end groups are two at both ends. The above-mentioned branching refers to an oligomer or a high molecular weight molecular chain that extends separately from a molecular chain (main chain) that corresponds to a trunk, and the property of the whole molecule is greatly changed by removing this.

  The radial rubber component is a rubber component having at least one branched chain in a molecular chain and having three or more so-called end groups. Radial rubber components include those in which the molecular chain shape of the entire molecule is a star shape, a comb shape, or the like.

  As the chain rubber component, a chain diene copolymer is preferable. Further, the content of the other monomer contained in the chain-type rubber component is preferably 25 to 65% by weight, more preferably 30 to 60% by weight, and more preferably 35 to 35% by weight with respect to the whole chain-type rubber component. More preferred is 55% by weight. When the content of the other monomer is 25% by weight or more, the cohesive force of the obtained hot melt adhesive composed of the rubber component-containing aqueous dispersion is maintained without lowering, while it is 65% by weight or less. The degree of curing of the adhesive is good, the texture of the adhesive body is good, and the adhesiveness is appropriately maintained.

  As the radial rubber component, a radial diene copolymer is preferable. Further, the content of the other monomer in the radial type rubber component is preferably 5 to 40% by weight, more preferably 10 to 35% by weight, and more preferably 15 to 30% by weight with respect to the whole radial type rubber component. Further preferred. When the content of the other monomer is 5% by weight or more, the cohesive force of the obtained hot melt adhesive composed of the rubber component-containing aqueous dispersion is maintained without being lowered, whereas it is 40% by weight or less. The degree of curing of the adhesive is good, the texture of the adhesive body is good, and the adhesiveness is appropriately maintained.

  The ratio (weight ratio) between the chain type rubber component and the radial type rubber component is preferably 10/90 or more, more preferably 20/80 or more, and further preferably 30/70 or more. Moreover, 90/10 is preferable, as for the upper limit of this ratio, 80/20 is more preferable, and 70/30 is further more preferable. By using the above ratio, it is possible to obtain a hot melt adhesive that has a high cohesive force when bonded and that is flexible.

<Tackifying resin (B)>
The tackifier resin (B) improves the initial adhesiveness by giving an adhesive force. Specific examples of the tackifying resin (B) include rosin, rosin derivative resin, terpene resin, coumarone-indene resin, petroleum resin, styrene resin, xylene resin, phenol resin, and hydrides of these resins. One or more kinds of resins to be selected may be mentioned (see Adhesion Technology 20, (2), 13 (2000)).

  The rosin derivative resin is preferably a rosin derivative resin having a number average molecular weight (Mn) of 200 to 1,000, and examples thereof include polymerized rosin and rosin ester. Further, as the terpene resin, terpene resins having a number average molecular weight (Mn) of 300 to 1200 are preferable. For example, (co) polymers such as α-pinene, β-pinene, limonene, and phenol-modified products thereof. Such as body.

  Further, the coumarone-indene resin is preferably a coumarone-indene resin having a number average molecular weight (Mn) of 300 to 1200. Furthermore, as the petroleum resin, a petroleum resin having a number average molecular weight (Mn) of 300 to 1200 is preferable. For example, (co) heavy such as C5 fraction, C9 fraction, C5 / C9 fraction, dicyclopentadiene, etc. Examples include coalescence.

  The styrene resin is preferably a styrene resin having a number average molecular weight (Mn) of 200 to 1,000 and a glass transition temperature (Tg) of 40 ° C. or higher, such as styrene, α-methylstyrene, Examples include (co) polymers such as vinyltoluene. Furthermore, as the xylene-based resin, a xylene-based resin having a number average molecular weight (Mn) of 300 to 3,000 is preferable, and examples thereof include a xylene-formaldehyde resin. Furthermore, as the phenolic resin, a phenolic resin having a number average molecular weight (Mn) of 300 to 3,000 is preferable, and examples thereof include a phenol-xylene-formaldehyde resin.

  Of these tackifier resins (B), more preferred are terpene-based hydrides and hydrides such as petroleum resin hydrides from the viewpoint of thermal stability, odor, and hue, and are particularly preferred. Is a hydride of a (co) polymerized petroleum resin of a C9 fraction, a C5 / C9 fraction, and a hydride of a (cyclo) diene-based (co) polymerized petroleum resin.

  The number average molecular weight (Mn) and the weight average molecular weight (Mw) described later are values obtained by gel permeation chromatography (GPC) method using polystyrene as a standard.

<Plasticizer (C)>
The plasticizer (C) is a component added for the purpose of lowering the melt viscosity of the rubber component (A), improving the miscibility with other components, and increasing the adhesive strength as an adhesive. Specific examples of the plasticizer (C) include paraffinic, naphthenic or aromatic process oils, hydrides of these liquid resins, natural or synthetic waxes, and mixtures of two or more thereof. (See Adhesion Technology 20, (2), 21 (2000)).

  The above paraffinic, naphthenic or aromatic process oil preferably has a weight average molecular weight (Mw) of 300 to 10,000, for example, liquid polybutene, liquid polybutadiene, liquid polyisoprene and the like at room temperature. Examples of the resin are liquid. The natural or synthetic waxes preferably have a weight average molecular weight (Mw) of 1,000 to 30,000. Examples thereof include paraffin wax, microcrystalline wax, and low molecular weight polyolefin wax.

  Among these, paraffinic process oil, naphthenic process oil, or a combination thereof is preferable from the viewpoint of obtaining a composition excellent in thermal stability and weather resistance.

<Amount of (A) component, (B) component, (C) component>
The rubber component-containing aqueous dispersion of the present invention is obtained by dispersing a rubber component-containing composition containing a rubber component (A), a tackifier resin (B), and a plasticizer (C) in water with the above-described polymer emulsifier. Manufactured. The content of the rubber component (A) relative to the total solid content of the rubber component-containing composition and the polymer emulsifier (hereinafter referred to as “solid content”) is the total solid content from the viewpoint of improving the cohesive strength. On the other hand, it is preferably 5% by weight or more, more preferably 10% by weight or more, and particularly preferably 12% by weight or more. If it is less than 5% by weight, the cohesive strength of the adhesive tends to be insufficient. On the other hand, considering the performance balance of the hot melt adhesive comprising the rubber component-containing aqueous dispersion of the present invention, the upper limit of the content of the rubber component (A) is preferably 40% by weight, more preferably 30% by weight, Particularly preferred is 25% by weight. When it is more than 40% by weight, the melt viscosity of the adhesive is increased and the initial adhesiveness may be deteriorated.

  In addition, the content of the tackifier resin (B) with respect to the total solid content is preferably 10% by weight or more, more preferably 20% by weight or more, particularly preferably 25%, based on the total weight, from the viewpoint of improving the adhesive strength. % By weight or more. If it is less than 10% by weight, the melt viscosity of the adhesive is increased, and the initial adhesiveness may be deteriorated. On the other hand, from the viewpoint of improving flexibility, the upper limit of the content of the tackifier resin (B) is preferably 70% by weight, more preferably 60% by weight, and particularly preferably 55% by weight. If it exceeds 70% by weight, the cohesive strength of the adhesive may be reduced.

  Furthermore, the content of the plasticizer (C) with respect to the total amount of the solid content is preferably 1% by weight or more, more preferably 5% by weight or more, particularly preferably 8% by weight or more based on the total weight from the viewpoint of melt viscosity. It is. When it is less than 1% by weight, the melt viscosity of the adhesive is increased, and the initial adhesiveness may be deteriorated. On the other hand, from the viewpoint of improving the cohesive force, the upper limit of the content of the plasticizer (C) is preferably 30% by weight, more preferably 25% by weight, and particularly preferably 22% by weight. If it exceeds 30% by weight, the cohesive strength of the adhesive may be reduced.

<Other additives (H)>
Furthermore, the rubber component-containing aqueous dispersion according to the present invention may contain other additives (H) depending on necessity or use.

  Examples of other additives (H) include antioxidants, ultraviolet absorbers, light stabilizers, organic or inorganic fillers, and the like. Examples of the antioxidant include hindered phenol compounds, phosphorus compounds, sulfur compounds, and the like.

  Specific examples of the hindered phenol compound include pentaerythryl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di- t-butyl-4-hydroxyphenyl) propionate and the like. Specific examples of the phosphorus compound include tris (2,4-di-t-butylphenyl) phosphite. Furthermore, specific examples of the sulfur compound include pentaerythryl-tetrakis (3-laurylthiopropionate), dilauryl-3,3'-thiodipropionate, and the like.

  Examples of the ultraviolet absorber include benzotriazole compounds such as 2- (3,5-di-t-amyl-2-hydroxyphenyl) benzotriazole and 2- (5-methyl-2-hydroxyphenyl) benzotriazole. Etc.

  Examples of the light stabilizer include hindered amine compounds and adsorbents. Specific examples of the hindered amine compound include (bis-2,2,6,6-tetramethyl-4-piperidyl) sebacate and the like, and specific examples of the adsorbent include alumina, silica gel, and molecular. Sheaves are examples.

  Examples of the organic or inorganic filler include talc, mica, calcium carbonate, titanium oxide, calcium oxide, and other pigments, dyes, and fragrances.

  When the other additive (H) is added, the amount of the additive is not particularly limited. For example, 0.01% for the antioxidant, the ultraviolet absorber, and the light stabilizer with respect to the total solid content. -5 wt% is preferred, more preferably 0.1-3 wt%. Moreover, in an adsorbent and a filler, 0.01 to 40 weight% is preferable, More preferably, it is 0.1 to 15 weight%. Furthermore, in a pigment, dye, and a fragrance | flavor, 0.005 to 2 weight% is preferable, More preferably, it is 0.01 to 1 weight%.

<Polymer emulsifier>
The said polymer emulsifier is an emulsifier used when the rubber component containing composition containing said rubber component (A), tackifying resin (B), and a plasticizer (C) is disperse | distributed to water. The weight average molecular weight (Mw) of the polymer emulsifier is preferably 1000 or more, and preferably 5000 or more. If it is less than 1000, the emulsion production stability tends to deteriorate. On the other hand, the upper limit of the weight average molecular weight (Mw) is preferably 1,000,000. If it exceeds 500,000, it tends to be difficult to stabilize the emulsifier on the resin surface, and handling tends to be difficult.

  As the polymer emulsifier, those having a cationic group, those having an anionic group, or those having a polarizable group or an amphoteric group are preferably used.

(Polymer emulsifier having a cationic group)
Examples of the polymer emulsifier having a cationic group include a partially neutralized product or a completely neutralized product of a copolymer obtained by copolymerizing the following components (D) and (E).

（式中、Ｒ_１はＨ又はＣＨ_３を示し、Ｒ_２は炭素数１〜４のアルキレン基又はヒドロキシ置換アルキレン基を示し、Ｒ_３及びＲ_４はＨ又は炭素数１〜４のアルキル基を示し、ＡはＯ又はＮＨを示す。） (D) component:

(In the formula, R ₁ represents H or CH ₃ , R ₂ represents an alkylene group having 1 to 4 carbon atoms or a hydroxy-substituted alkylene group, and R ₃ and R ₄ represent H or an alkyl group having 1 to 4 carbon atoms. A represents O or NH.)

（Ｅ）成分：α、β−不飽和カルボン酸アルキルエステル。 And / or

(E) Component: α, β-unsaturated carboxylic acid alkyl ester.

  Specific examples of the component (D) include N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylamide, N, N- Examples thereof include dimethylamino-2-aminoethyl (meth) acrylate, 2-vinylpyridine, 4-vinylpyridine and the like.

  Specific examples of the component (E) include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, Examples thereof include stearyl (meth) acrylate, cyclohexyl (meth) acrylate, allyl (meth) acrylate, and the like. These may be used alone or in combination. In the present specification, “(meth) acryl” means “acryl or methacryl”.

  Among these, as the component (E), methacrylic acid having 6 or more carbon atoms in the alkyl group such as methyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, tridecyl methacrylate, stearyl methacrylate, etc. Those having alkyl etesul as the main component are preferred.

  The blending ratio (molar ratio) between the component (D) and the component (E) is (D) / (E), preferably 10/90 or more, and more preferably 25/75 or more. If it is less than 10/90, the hydrophilicity of the resulting neutralized copolymer becomes weak and it may be difficult to produce a stable aqueous dispersion. On the other hand, the upper limit of (D) / (E) is preferably 80/20, preferably 60/40, and particularly preferably 50/50. If it is larger than 80/20, the neutralized product of the copolymer obtained is too hydrophilic and it may be difficult to produce a stable aqueous dispersion. In particular, when (D) / (E) is 50/50 or less, the rubber component (A), the tackifier resin (B), and the plasticizer (C) have a good affinity and are hydrophilic as a dispersant. Is particularly preferred because it has the advantage of high emulsifying power.

  The cationic group-containing polymer emulsifier is neutralized with a neutralizing agent as necessary. The degree of neutralization is preferably 50 to 100%, and preferably 80 to 100. If the degree of neutralization is less than 50%, the solubility of the copolymer in water deteriorates, the particle size of the resulting aqueous dispersion increases, and separation between the resin layer and the aqueous layer tends to occur. .

  Examples of the neutralizing agent include formic acid, acetic acid, hydrochloric acid, phosphoric acid, and nitric acid. Among these, when using volatile formic acid, acetic acid, and hydrochloric acid that are volatile at room temperature, an aqueous dispersion containing a rubber component is obtained. When the film is dried to form a film, these acids are liberated from the neutralized product, the hydrophobicity of the polymer dispersant is increased, and the water resistance of the film is improved.

  The said neutralization reaction is implemented by making the copolymer and acidic compound concerning the said cationic group containing polymeric emulsifier react at 20-100 degreeC for 0.1 to 3 hours.

  The neutralized product of the copolymer of the present invention can also be produced by previously neutralizing the component (D) with the above-described neutralizing agent and copolymerizing this with the component (E). .

  In addition to the above components (D) and (E), polymerizable monomers such as vinyl acetate, styrene and vinyl ether can be used as necessary.

  The copolymer constituting the polymeric emulsifier having a cationic group is 0 to 180 ° C., preferably 40 to 120 ° C., for 0.5 to 20 hours, preferably 2 to 10 hours in the presence of a polymerization initiator. Produced by reacting. This copolymer is preferably carried out in the presence of a hydrophilic solvent such as ethanol, isopropanol or cellosolve.

  As the polymerization initiator, an initiator comprising a persulfate such as ammonium persulfate, potassium persulfate, sodium persulfate, etc., a redox initiator using the persulfate in combination with a sulfite, a thiosulfate reducing agent, Redox initiators using organic peroxides such as lauroyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, etc., or iron (II) salt, sulfite, thiosulfate reducing agents, etc. -Azobis (isobutyronitrile), 2,2'-azobis [2-methyl-N- (2-hydroxyethyl) propionamide], 2,2'-azobis [2- (2-imidazolin-2-yl) Propane] dihydrochloride, 2,2'-azobis (2-methylpropionamidine) dihydrochloride and other azo compounds, t-butyl Oxy isobutyrate, 1,1-bis (t-butylperoxy) cyclohexene, t- butyl peroxybenzoate, and the like. The amount of the polymerization initiator used is preferably 0.01 to 10% by weight based on the total amount of monomers used.

  The use amount (solid content) of the polymeric emulsifier having a cationic group is preferably 2% by weight or more, preferably 3% by weight or more, and more preferably 5% by weight or more based on the total solid content. If it is less than 2% by weight, it may be difficult to produce a stable aqueous dispersion. On the other hand, the upper limit of the amount used (solid content) is preferably 30% by weight, preferably 20% by weight, and more preferably 15% by weight. If it exceeds 30% by weight, water resistance and adhesive strength may be lowered.

(Polymer emulsifier having an anionic group)
Examples of the polymer emulsifier having an anionic group include a partially neutralized product or a completely neutralized product of a copolymer obtained by copolymerizing the following components (F) and (G).
(F) Component: α, β-unsaturated carboxylic acid (G) Component: α, β-unsaturated carboxylic acid alkyl ester

  Specific examples of the component (F) include acrylic acid, methacrylic acid, itaconic acid, citraconic acid, maleic acid, crotonic acid, fumaric acid, fumaric acid, and monoalkyl esters of maleic acid. Two or more of these may be used in combination.

  Examples of the component (G) include (meth) acrylic acid esters having an ester carbon number of 1 to 22, and specific examples include methyl (meth) acrylate, ethyl (meth) acrylate, Examples include butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, allyl (meth) acrylate, and the like. They may be used or used in combination.

  Among these, (meth) acrylic acid ester having 1 to 3 carbon atoms in the ester is 20 to 70 mol% in the monomer, and (meth) acrylic acid ester having 4 to 22 carbon atoms in the monomer is the monomer. When used in combination of two or more at a ratio of 30 to 80 mol%, the rubber component (A), the tackifier resin (B), and the plasticizer (C) have good affinity, and the dispersant is hydrophilic and lipophilic. Is particularly preferable since the balance is improved and the dispersibility is improved.

  The blending ratio (molar ratio) of the component (F) and the component (G) is (F) / (G), preferably 10/90 or more, and more preferably 15/85 or more. If it is less than 10/90, the hydrophilicity of the copolymer neutralized product becomes weak, and it may be difficult to produce a stable aqueous dispersion. On the other hand, the upper limit of (D) / (E) is preferably 80/20, and preferably 75/25. If it is larger than 80/20, it may be difficult to produce a stable aqueous dispersion because the neutralized product is too hydrophilic.

  The anionic group-containing polymer emulsifier is neutralized with a neutralizing agent as necessary. The degree of neutralization is preferably 50 to 100%, and preferably 60 to 100%. If the degree of neutralization is less than 50%, the solubility of the copolymer in water deteriorates, the particle size of the resulting aqueous dispersion increases, and separation between the resin layer and the aqueous layer tends to occur. .

  Examples of the neutralizing agent include alkali hydroxides such as sodium hydroxide and potassium hydroxide, alkylamines such as ammonia, methylamine, dimethylamine, trimethylamine and ethylamine, and alkanolamines such as 2-amino-2-methylpropanol. And morpholine. Among these, when a low boiling point substance such as ammonia or a lower alkylamine having 1 to 4 carbon atoms is used, these basic compounds are easily released from the polymer emulsifier when the obtained aqueous dispersion is dried to form a film. It is preferable because the hydrophobicity of the dispersant incorporated in the film is increased and the water resistance of the film is improved.

  The said neutralization reaction is implemented by making the copolymer and basic compound concerning the said anionic group containing polymeric emulsifier react at 20-100 degreeC for 0.1 to 3 hours.

  The neutralized product of the copolymer of the present invention can also be produced by previously neutralizing the component (F) with the neutralizing agent and copolymerizing the component (G) with the component (G). .

  In addition to the components (F) and (G), polymerizable monomers such as vinyl acetate, styrene, and vinyl ether can be used as necessary.

  The copolymer constituting the polymer emulsifier having an anionic group is 0 to 180 ° C., preferably 40 to 120 ° C., for 0.5 to 20 hours, preferably 2 to 10 hours in the presence of a polymerization initiator. Produced by reacting. This copolymer is preferably carried out in the presence of a hydrophilic solvent such as ethanol, isopropanol or cellosolve.

  Examples of the polymerization initiator include azobisisobutyronitrile, t-butylperoxyisobutyrate, 1,1-bis (t-butylperoxy) cyclohexene, t-butylperoxybenzoate, and the like.

  The use amount (solid content) of the polymer emulsifier having an anionic group is preferably 2% by weight or more, preferably 3% by weight or more, and more preferably 5% by weight or more based on the total solid content. If it is less than 2% by weight, it may be difficult to produce a stable aqueous dispersion. On the other hand, the upper limit of the amount used (solid content) is preferably 30% by weight, preferably 20% by weight, and more preferably 15% by weight. If it exceeds 30% by weight, water resistance and adhesive strength may be lowered.

<Method for producing rubber component-containing aqueous dispersion>
Although it does not specifically limit as a manufacturing method of the rubber component containing aqueous dispersion used for the hot-melt-bonding | bonding of this invention, The following two methods can be mentioned.

  As a first method, a rubber component (A), a tackifier resin (B), and a plasticizer (C) are heated and melt mixed to obtain a rubber component-containing composition, and then water and a polymer emulsifier are used. And a method of dispersing in water by stirring shear force.

  As a second method, a rubber component (A), a tackifier resin (B), a plasticizer (C) and an organic solvent (toluene, xylene, etc.) are added and each component is heated as necessary. There is a method in which after dissolving and obtaining a solution of the rubber component-containing composition, the solvent is distilled off after uniform mixing by shearing force in the presence of water and a polymer emulsifier.

  The industrially preferred method is the first method that does not use an organic solvent. Therefore, detailed conditions of the first method will be described.

  Each of the above components is heated and melted and mixed, but the kneader used for this is not particularly limited in its form and shape, but for example, a pressure reactor with a stirrer, a compressible Examples include a mixer having a high shape screw or ribbon stirrer, a kneader, a single or multi-screw extruder as disclosed in JP 56-2149, a Banbury mixer, a roll mill, a kneader, an ink roll, and the like. be able to.

  The temperature of the above-mentioned heat-melt mixing is usually 80 to 200 ° C., and it is preferably performed in an inert gas atmosphere such as nitrogen gas in order to prevent the deterioration of the resin.

  The rubber component-containing aqueous dispersion according to the present invention can be obtained by mixing these heat-melted mixture with water and a polymer emulsifier and further continuing kneading. In addition, in order to adjust viscosity etc., you may mix water with said rubber component containing water dispersion liquid.

  The viscosity at room temperature of the rubber component-containing aqueous dispersion according to the present invention is 10 to 10,000 mPa · s, more preferably 10 to 8,000 mPa · s, and particularly preferably 10 to 5,000 mPa · s. is there. When it exceeds 10,000 mPa · s, handling and coating properties are unsatisfactory. On the other hand, when it is less than 10 mPa · s, the aqueous dispersion tends to flow on the substrate, and there is a tendency that sagging or thick coating becomes difficult.

<Application>
The rubber component-containing aqueous dispersion according to the present invention can be used as a hot melt adhesive. Specifically, the rubber component-containing aqueous dispersion is applied to one or both of the objects to be bonded by a method such as application, immersion, spraying, and the like, and dried to form an adhesive layer on the object to be bonded. . Next, the temperature is raised above the softening point of the rubber component, the adhesive layer is melted, brought into contact with the adherend, and bonded. Thereby, the adhesive body bonded by using a rubber component containing water dispersion liquid can be obtained.

  Examples of the object to be bonded include resin molded products such as polyolefin resin molded products. Examples of the adherend include resin molded products such as polyolefin resin molded products and other substances.

  Examples of the resin molded product include molded products such as films, sheets, woven fabrics, nonwoven fabrics, injection molded products, and compressed air molded products.

  Hereinafter, the present invention will be described more specifically with reference to examples. First, the evaluation method and the raw materials used will be described.

(Evaluation methods)
<Aqueous dispersion viscosity measurement>
200 g of the aqueous dispersion sample was placed in a 250 ml plastic bottle, covered, and immersed in a constant temperature water bath at 25 ° C. for 3 hours. The plastic bottle was taken out, and the viscosity after rotation for 1 minute was measured using a viscometer (manufactured by Tokyo Keiki Co., Ltd .: B-type viscometer No. 2 rotor, 60 rpm).

<Coating property>
In order to compare the ease of application (permeability of the aqueous dispersion into the nonwoven fabric), the following criteria describe the situation in which the aqueous dispersion is applied by spraying (application amount: 20 g / m ² ) and absorbed into the nonwoven fabric. It was evaluated with.
○: The aqueous dispersion is rapidly and uniformly absorbed. Can be applied.
X: Unevenness occurs without the water dispersion being absorbed. Coating is impossible.

<Adhesive texture>
An aqueous dispersion is applied to a polypropylene nonwoven fabric having a length of 100 mm, a width of 25 mm, and a thickness of 100 μm by spraying at a width of 25 mm (coating amount: 10 g / m ^{2 in} solid content), dried with hot air at 50 ° C., and then polypropylene having the same size The non-woven fabric was sandwiched from above and below and heated and pressed at 150 ° C. for bonding. After leaving for 24 hours in an atmosphere of 25 ° C., the texture was evaluated by touch according to the following criteria.
○: The texture of the nonwoven fabric is not impaired (same as no adhesive)
Δ: Inferior to the texture of the non-coated nonwoven fabric ×: The texture of the nonwoven fabric is remarkably impaired

<Storage stability and odor confirmation of aqueous dispersion>
100 g of the aqueous dispersion sample was placed in a 200 ml glass bottle, covered, and left in a 50 ° C. circulation-type air dryer for 10 days. The bottle was taken out every day, and the glass bottle was tilted to confirm the presence or absence of aggregates. Further, after 10 days, the lid was opened and odor was confirmed. And it evaluated on the following reference | standard.
-Storage stability (circle): Even if 10 days passed, generation | occurrence | production of the aggregate etc. was not seen.
Xn: Generation of aggregates and the like was observed on the nth day.
・ Odor ○: There was no odor.
X: There was an odor.

<T-type peel adhesion strength>
The aqueous dispersion was applied to a polypropylene nonwoven fabric having a length of 100 mm × width 25 mm × thickness 100 μm in a width of 25 mm by spraying (solid content 6 g / m ² ), dried, and bonded to a polypropylene nonwoven fabric of the same size, 150 It was heated and pressed at 0 ° C. for adhesion. After leaving for 24 hours in an atmosphere at 25 ° C., the peel strength is measured at a tensile speed of 300 mm / min using a tensile tester (Autocom AC-50C (manufactured by TS KK)), and the maximum value is obtained. T-type peel adhesion strength was used (unit: N · g / 25 mm).

(raw materials)
<Rubber component (A)>
Styrene-butadiene block copolymer rubber: manufactured by Clayton Polymer Japan Co., Ltd .: Clayton D-1155, styrene content 40% by weight; MI = 14 (corresponding to linear rubber component), hereinafter referred to as “A-1”.
-Styrene-butadiene block copolymer rubber manufactured by Kraton Polymer Japan, Inc .: Kraton D-1116, styrene content 23% by weight; MI≤1, (corresponding to radial type rubber component), hereinafter referred to as "A-2".
<Tackifying resin (B)>
-Partially hydrogenated petroleum resin (C9 fraction copolymer main component) ... Arakawa Chemical Co., Ltd. product: "Arcon M-115, softening point = 115 ° C, hereinafter referred to as" B-1 ".
<Plasticizer (C)>
-Naphthenic oil: Idemitsu Kosan Co., Ltd .: Diana Process Oil NP-24, hereinafter referred to as “C-1”.
<(D) component>
N, N-dimethylaminoethyl methacrylate: Sanyo Chemical Industries, Ltd .: Methacrylate DMA, hereinafter abbreviated as “DMA”.
<(E) component, (G) component>
・ Methyl methacrylate: manufactured by Mitsubishi Rayon Co., Ltd., hereinafter abbreviated as “MMA”.
-Butyl methacrylate: manufactured by Mitsubishi Rayon Co., Ltd., hereinafter abbreviated as “BMA”.
Lauryl methacrylate: Mitsubishi Rayon Co., Ltd., hereinafter abbreviated as “SLMA”.
<(F) component>
Acrylic acid: manufactured by Mitsubishi Chemical Corporation, hereinafter abbreviated as “AA”.
Methacrylic acid: Mitsubishi Rayon Co., Ltd., hereinafter abbreviated as “MAA”.
<Other additives (H)>
Hindered phenolic antioxidant: Ciba Specialty Chemicals Co., Ltd .: Irganox 1010, hereinafter referred to as “H-1”.
Phosphorus antioxidant: manufactured by Asahi Denka Kogyo Co., Ltd .: ADK STAB 2112, hereinafter referred to as “H-2”.
Benzotriazole ultraviolet absorber: Ciba Specialty Chemicals Co., Ltd .: Tinuvin 328, hereinafter referred to as “H-3”.
<Others>
Isopropyl alcohol: manufactured by Tokuyama Corporation, hereinafter abbreviated as “IPA”.

(Manufacture of polymer emulsifier)
(Production Examples 1 and 2)
In a 150 L reactor equipped with a cooler, a nitrogen introduction tube, a stirrer, a monomer dropping funnel and a heating jacket, each component shown in Table 1 was charged in the amount shown in Table 1, and after replacing with nitrogen, the internal temperature was adjusted. The temperature was raised to 80 ° C. Furthermore, 400 g of a polymerization initiator (2,2′-azobisisobutyronitrile) in an amount shown in Table 1 was added to initiate polymerization. The polymerization was continued for 4 hours while maintaining the temperature at 80 ° C. Next, after neutralizing with the neutralizing agent in the amount shown in Table 1, water was added while distilling off the IPA to replace the viscous acrylic copolymer finally neutralized by 100 mol%. Cationic polymer emulsifier (Production Example 1) or neutralized aqueous solution of anionic polymer emulsifier (Production Example 2) (hereinafter referred to as “EM1” (Production Example 1), “EM2” (Production Example 2)) (The yield was 97% for all).

(Examples 1 and 2)
The first liquid mixed with the formulation (parts by weight) shown in Table 2 at a rate of 100 parts / hour is the same direction rotary meshing twin screw extruder (Ikegai Iron Works, trade name: PCM45, Sanjo Hijiri) It was continuously supplied from a hopper of a groove type, L / D = 30).
Further, a second pump obtained by adding water to the polymer emulsifier aqueous solution shown in Table 2 from a supply port provided in the vent portion of the extruder at a rate of 170 parts / hour is a gear pump (discharge pressure 3 kg / cm ² ). While being pressurized and continuously supplied, the mixture was continuously extruded at a heating temperature (cylinder temperature, the same applies hereinafter) at 130 ° C. and a screw rotation speed of 100 rpm to obtain an aqueous dispersion. Said evaluation test was done about the obtained aqueous dispersion. The results are shown in Table 2.

(Comparative Examples 1 and 2)
The 1st liquid was manufactured by mixing with the mixing | blending prescription (part by weight) shown in Table 2. A difference between Examples 1 and 2 is that a surfactant (sodium dodecylbenzenesulfonate (manufactured by Tokyo Chemical Industry Co., Ltd.)) and toluene (manufactured by Tokyo Chemical Industry Co., Ltd.) are used instead of the polymer emulsifier. ). And said evaluation test was done using this 1st liquid. The results are shown in Table 2.

Claims (8)

  A rubber component-containing composition containing a rubber component (A) selected from a diene copolymer and an ethylene-α-olefin copolymer, a tackifier resin (B), and a plasticizer (C) is treated with a polymer emulsifier. A rubber component-containing aqueous dispersion dispersed in the composition.   The diene copolymer as the rubber component (A) is at least one selected from the group consisting of a styrene-butadiene block copolymer, a styrene-isoprene block copolymer, and a hydride thereof. The rubber component-containing aqueous dispersion described. In the part of the copolymer obtained by copolymerizing the following component (D) and component (E) in a molar ratio of (D) / (E) = 10/90 to 80/20. The rubber component-containing aqueous dispersion according to claim 1 or 2, comprising a Japanese or completely neutralized product.
(D) component:

(In the formula, R ₁ represents H or CH ₃ , R ₂ represents an alkylene group having 1 to 4 carbon atoms or a hydroxy-substituted alkylene group, and R ₃ and R ₄ represent H or an alkyl group having 1 to 4 carbon atoms. A represents O or NH.)
And / or

(E) component:
α, β-unsaturated carboxylic acid alkyl ester. In the part of the copolymer obtained by copolymerizing the following component (F) and component (G) at a molar ratio of (F) / (G) = 10/90 to 80/20: The rubber component-containing aqueous dispersion according to claim 1 or 2, comprising a Japanese or completely neutralized product.
(F) component: α, β-unsaturated carboxylic acid (G) component: α, β-unsaturated carboxylic acid alkyl ester   The rubber component-containing aqueous dispersion according to any one of claims 1 to 4, wherein the component (A) contains two types of a linear rubber component and a radial rubber component.   6. The rubber component-containing water according to claim 5, wherein the ratio (weight ratio) between the linear rubber component and the radial rubber component is 10/90 to 90/10 in terms of linear rubber component / radial rubber component. Dispersion.   The rubber component-containing aqueous dispersion according to any one of claims 1 to 6, produced using a kneader selected from a roll mill, a kneader, an extruder, an ink roll, and a Banbury mixer.   The adhesive body formed by adhere | attaching polyolefin resin molded articles or polyolefin resin molded articles and another adherend using the rubber component containing aqueous dispersion in any one of Claims 1-7.