JP2010007043A - Aqueous composite resin dispersion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aqueous composite resin dispersion of polyurethane-polychloroprene excellent in stability and adhesive performance of the dispersion. <P>SOLUTION: In the aqueous composite resin dispersion, composite resin particles comprising polyurethane and polychloroprene are dispersed in an aqueous medium with the weight ratio of the polyurethane to the polychloroprene being 99/1 to 20/80, and the pH being 7 to 10. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an aqueous composite resin dispersion, and more specifically, is a polyurethane-polychloroprene aqueous composite resin dispersion excellent in dispersion stability and adhesive performance.

  Conventionally, solvent systems have been the mainstream in the adhesive field. However, in recent years, harmfulness to human bodies, safety, and air pollution have come to be regarded as problems, and expectations for water-based adhesives as an alternative are increasing. Under these circumstances, various adhesives using aqueous polyurethane-based or aqueous chloroprene-based resin dispersions have been studied, and a technique for improving adhesive performance by using these resin dispersions in combination is also disclosed. (For example, Patent Documents 1 and 2).

  However, a dispersion in which an aqueous polyurethane and an aqueous polychloroprene are mixed has a problem in stability. Aqueous polychloroprene is usually polymerized and dispersed and stabilized under strong alkalinity, such as rosinate, to maintain adhesion performance and prevent dehydrochlorination, and the coexisting polyurethane is hydrolyzed to reduce molecular weight. The adhesive performance is reduced.

  On the other hand, techniques for obtaining aqueous composite resin dispersions by radical polymerization of aqueous polyurethane and acrylic monomers are disclosed (for example, Patent Documents 3 and 4). According to these composite resin dispersions, the stability is increased as compared with the case where the two polymer dispersions are simply mixed, and an improvement effect such as adhesion performance is shown.

  However, due to the problem of the stability of the dispersion derived from the dehydrochlorination of polychloroprene and the problem of the poor compatibility between polyurethane and polychloroprene, etc. The dispersion is not shown.

JP 2001-3021 A Special table 2007-533778 JP 59-138212 A JP 2007-119521 A

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a polyurethane-polychloroprene aqueous composite resin dispersion having excellent dispersion stability and adhesive performance.

  As a result of intensive studies to solve the above problems, the present inventors have found the following aqueous composite resin dispersion, and have completed the present invention. That is, in the present invention, composite resin particles containing polyurethane and polychloroprene are dispersed in an aqueous medium, the weight ratio of polyurethane to polychloroprene is 99/1 to 20/80, and the pH is 7 to 10. It is an aqueous composite resin dispersion characterized by being.

  Hereinafter, the present invention will be described in more detail.

  The aqueous composite resin dispersion of the present invention is one in which composite resin particles containing polyurethane and polychloroprene are dispersed in an aqueous medium. When the composite resin particle contains polyurethane and polychloroprene, it can be made a composite particle having toughness and flexibility, and when the composite resin particle is dispersed in an aqueous medium, a non-solvent type It can be applied as a paint or adhesive.

  In the aqueous composite resin dispersion of the present invention, the weight ratio of polyurethane to polychloroprene is 99/1 to 20/80. If the ratio of polychloroprene exceeds 80, the dispersion stability may be lowered.

  The aqueous composite resin dispersion of the present invention has a pH of 7-10. If the pH is less than 7, dehydrochlorination is likely to occur during storage, the stability of the dispersion decreases, scale precipitation occurs, and further, hydrolysis of the polyurethane proceeds, leading to a decrease in adhesion. . On the other hand, if the pH exceeds 10, hydrolysis of the polyurethane tends to occur, resulting in a decrease in adhesion performance.

  The aqueous composite resin dispersion of the present invention can be obtained, for example, by radical polymerization of a chloroprene monomer in an aqueous polyurethane dispersion having a pH of 7 to 10. More specifically, polymerization is performed by adding a chloroprene monomer, a radical polymerization initiator, and, if necessary, a reducing agent, a molecular weight regulator, and optionally other vinyl monomers to an aqueous polyurethane dispersion. It is. There is no particular limitation on the weight of the chloroprene monomer and polyurethane, but the weight composition ratio is preferably polyurethane / polychloroprene = 99/1 to 15/85.

  As the radical polymerization initiator, a polymerization initiator used in usual emulsion polymerization can be applied. For example, persulfates such as ammonium persulfate, potassium persulfate, and sodium persulfate, azo compounds such as 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), Examples include radical initiators such as peroxides such as hydrogen peroxide, t-butyl hydroperoxide, cumene hydroperoxide, benzoyl peroxide, lauryl peroxide, and these may be used alone or in combination of two or more. Can do. These radical polymerization initiators and reducing agents such as sodium sulfite, sodium hydrogen sulfite, sodium thiosulfate, tartaric acid, L-ascorbic acid, D-ascorbic acid (erythorbic acid), ferrous sulfate, dimethylaniline, etc. Can be used together to form a redox initiator system. Although the usage-amount of a radical polymerization initiator does not have limitation in particular, For example, it is 0.01 to 3 weight% on the basis of the weight of a chloroprene monomer, Especially 0.05 to 1 weight%. Further, the amount of the reducing agent used is not particularly limited, but the same amount as that of the polymerization initiator is preferable. As a method for adding the polymerization initiator and the reducing agent, any one of a method in which batch addition is performed in the initial stage, a method in which addition is performed in the middle of polymerization, or a method in which dripping is continuously performed is employed.

  Examples of the molecular weight regulator include mercaptans such as n-dodecyl mercaptan, n-octyl mercaptan, t-butyl mercaptan, thioglycolic acid and thiomalic acid, and sulfides such as diisopropylxanthogen disulfide, diethylxanthogen disulfide and diethyltyramium disulfide. , Dithiocarboxylic acid esters such as benzyldithiobenzoate and 2-cyanopropyldithiobenzoate, halogenated hydrocarbons such as iodoform, diphenylethylene, p-methylstyrene dimer, and sulfur. The usage-amount of a molecular weight regulator is the range of 0 to 3 weight% on the basis of the weight of a chloroprene monomer, for example.

  In the present invention, the chloroprene monomer alone is used for radical polymerization, and in some cases, it can be copolymerized with other vinyl monomers. Examples of other vinyl monomers include diene monomers such as 2,3-dichloro-1,3-butadiene, 1-chloro-1,3-butadiene, isoprene and 1,3-butadiene, and olefin monomers such as butene. (Meth) acrylic acid ester monomers such as butyl (meth) acrylate, methacrylic acid-dimethylaminomethyl, methacrylic acid-dimethylaminoethyl, acrylic acid, methacrylic acid, 2-methacryloxyethyl succinic acid, 2-methacryloyl Examples thereof include unsaturated fatty acids such as loxyethylhexahydrophthalic acid, fumaric acid, maleic anhydride, and crotonic acid, and vinyl acetate.

  The concentration of polyurethane and chloroprene monomer during chloroprene monomer polymerization is not particularly limited, but from the viewpoint of polymerization efficiency and dispersion stability, polyurethane is 5 to 50% by weight, chloroprene monomer is 1 to 50% by weight, and both are combined. The substrate concentration is preferably in the range of 10 to 60% by weight. The polyurethane polymerization temperature and time are not particularly limited, and for example, polymerization can be performed in a temperature range of 0 to 50 ° C. for 0.5 to 30 hours.

  The polyurethane-polychloroprene aqueous composite resin dispersion thus obtained can be applied as it is as an adhesive, but is more preferably concentrated by an evaporator or the like to adjust the solid content concentration to 40 to 60% by weight. .

  The aqueous polyurethane dispersion used for the production of the aqueous composite resin dispersion of the present invention has a pH of 7-10. This is because the pH range of the aqueous composite resin dispersion of the present invention depends on the pH of the aqueous polyurethane dispersion as the raw material. The particle diameter of polyurethane is preferably 50 to 300 nm, and it is preferable for the dispersion stability and adhesion performance of the aqueous composite resin dispersion to be in this range.

  The composition of the polyurethane is not particularly limited, and for example, a polyurethane composed of a hydrophilizing agent of a diamino compound containing a polyol, diisocyanate, or a sulfonate group and an amine chain extender is preferable. In this polyurethane, a urethane prepolymer obtained by reacting a polyol and a diisocyanate is mixed with a hydrophilizing agent containing a sulfonate in a solution having affinity for water such as acetone, and an amine chain such as triethanolamine. It is obtained by reacting with an extender, adding water to the polymer solution obtained under stirring to form a dispersion, and then removing the solvent.

  The polyol is not particularly limited. For example, a polyester-based polyol, a polyether-based polyol, a polycarbonate-based polyol, or the like is selected, and a combination of these two or more polyols, or a low-molecular weight polyol having a molecular weight of less than 300, if necessary. Can be used in combination. Of these, polyester polyols are preferred from the standpoint of stability during preparation or storage of the polyurethane-polychloroprene aqueous composite dispersion and adhesive performance. Examples of polycarboxylic acid components in polyester polyols include succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, maleic anhydride, fumaric acid, etc. Can be mentioned. On the other hand, examples of the polyol compound include ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, Neopentyl glycol, diethylene glycol, dipropylene glycol, 3-methyl-1,5-pentanediol, 1,4-cyclohexanediol and the like can be mentioned. The molecular weight of the polyol is not particularly limited, but for example, those having a molecular weight in the range of 500 to 5000 are preferably used.

  The diisocyanate is not particularly limited, and examples thereof include 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,12-dodecamethylene diisocyanate, 1-isocyanato-3-cyanatomethyl-3,5,5-trimethyl- Cyclohexane (isophorone diisocyanate), cyclohexane-1,3- and / or 1,4-diisocyanate, bis- (4-isocyanatocyclohexyl) -methane, 2,4′-diisocyanato-dicyclohexylmethane, α, α, α ′ , Α′-tetramethyl-1,3- and / or 1,4-xylylene diisocyanate, 2,4- and / or 2,6-hexahydrotoluylene diisocyanate, 1,3- and / or 1,4- Phenylene diisocyanate, 2,4- and / or 2 6-toluylene diisocyanate, 2,4- and / or 4,4'-diphenylmethane diisocyanate.

  The hydrophilizing agent for the diamino compound containing a sulfonate group is not particularly limited. For example, sodium 2- (2-aminoethyl) aminoethanesulfonate, 2- [β- (β-aminoethyl) amino-propionamide ] -2 · 2-dimethylethanesulfonic acid sodium salt, ethylenediamino-N, N′-bis [(γ-propionamide) -2 · 2-dimethylethanesulfonic acid sodium salt], 2- (2-aminoethyl) aminoethane Sodium benzenesulfonate and ethylenediamino-N, N′-bis (sodium β-ethylbenzenesulfonate) are exemplified as preferable examples. The amount of the hydrophilizing agent to be added is not particularly limited, but in order to obtain a stable aqueous polyurethane dispersion, it is preferably in the range of 0.02 to 0.2 mol per gram of urethane prepolymer.

  The amine chain extender is not particularly limited, and examples thereof include piperazine and alkylenediamines such as ethylenediamine, alkanolamines such as diethanolamine and triethanolamine, and the like. Among them, application of alkanolamine having tertiary nitrogen is more preferable in terms of adjustment to pH range 7 to 10 and ease of control of molecular weight. The alkanolamine having tertiary nitrogen is not particularly limited, and examples thereof include triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, N-methyldiisopropanolamine, and N-ethyldiisopropanolamine.

  The aqueous composite resin dispersion of the present invention can be used in combination with an emulsifier as long as the effects of the present invention are not impaired. Although there is no particular limitation, for example, nonionic emulsifiers such as polyoxyethylene decylate, polyoxyethylene laurate, polyoxyethylene cetylate, polyoxyethylene stearate, polyoxyethylene nonyl phenylate are suitable. The emulsifier is preferably 5% by weight or less, more preferably 3% by weight or less, based on the resin solid content.

  Further, a curing agent can be added to the aqueous composite resin dispersion of the present invention for the purpose of improving water resistance, heat resistance and the like. Examples of the curing agent include polyfunctional compounds such as amino resins, epoxy compounds, carbodiimide compounds, oxazoline compounds, and polyisocyanate compounds. Among these, polyisocyanate compounds are preferable. The addition amount of a hardening | curing agent can be used in 0.5-20 weight% with respect to polyurethane resin solid content.

  Furthermore, the aqueous composite resin dispersion of the present invention may be used alone, but an aqueous resin dispersion such as SBR latex, acrylic emulsion, poly (ethylene-vinyl acetate) emulsion or the like may be used in combination.

  In addition, in the field of adhesive application, the aqueous composite resin dispersion of the present invention is a thickener, a plasticizer, a tackifier, a pigment, an antifoaming agent, an oxidation agent, etc. Inhibitors, preservatives, ultraviolet absorbers, flame retardants and the like can also be used.

  According to the present invention, a polyurethane-polychloroprene aqueous composite resin dispersion having excellent dispersion stability and adhesive performance is provided, and can be applied to paints, primers, sealants, etc. in addition to adhesives. Yes, it is extremely useful industrially.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto.

<Calculation of polymerization rate>
The measurement was performed by measuring the solid content (% by weight) of the polymerization reaction solution. The solid content was measured by drying the polymerization solution sampled at 170 ° C. for 15 minutes, and the solid content was measured from the change in weight before and after drying. Solid content of polyurethane (PU solid content), solid content of polychloroprene when the polymerization rate of chloroprene reaches 100% (CR 100% polymerization solid content), and actual measured solid value (measured solids) The calculation was performed using the following formula.
Chloroprene polymerization rate (%) = {(measured solid content−PU solid content) / CR 100% polymerization solid content} × 100
<Measurement of particle size>
The particle size of the polyurethane dispersion and the polyurethane-polychloroprene aqueous composite dispersion was set using a Microtrac UPA150 (manufactured by Nikkiso Co., Ltd.) and the refractive index of the dispersion medium was set to 1.33. Measurement and median particle size were determined.

<Measurement of weight average molecular weight>
The weight average molecular weight (Mw) was measured by GPC8220 manufactured by Tosoh Corporation under the following conditions (eluent = tetrahydrofuran, flow rate = 1.0 ml / min, column temperature 40 ° C., peak detection = RI detector, column = TSK−). gel (registered trademark, the same applies hereinafter) G7000Hxl / GMHxl / GMHxl / G3000Hxl / guard column HL, molecular weight calculation = polystyrene conversion).

<Evaluation of dispersion stability>
25 g of the polyurethane-polychloroprene aqueous composite resin dispersion was placed in a 30 ml sample bottle and allowed to stand at room temperature (23 ° C.) for 1 month, and the presence and amount of precipitates were evaluated. When the sediment is less than 0.1% by weight, it is indicated by ◯, when the precipitate is 0.1% by weight to less than 1% by weight of the total solid, Δ, and when it is 1% by weight or more of the total solid, it is indicated by ×. did.

<Measurement of normal temperature adhesive strength>
No. 9 canvas (150 mm x 25 mm) was used as a base material, and about 300 g / m ² was applied to both sides of the ^two canvases with a brush, dried at 80 ° C for 5 minutes, and then two hand rollers A test piece was prepared by pressure-bonding. The room temperature adhesive strength was measured by performing a 180 ° peel test under the condition of 100 mm / min with a Tensilon type tensile tester. What was measured immediately after crimping was the initial strength, and that measured after one day was the strength after one day. In addition, the peeled state of the adhesive surface when the peel strength after one day was measured was observed, and what was peeled off at the interface between the base material and the adhesive layer (unfavorable peel) was “interfacial peel”, and the base material was adhered. A case where the adhesive layer was broken and peeled while the adhesive layer was adhered (preferable peeling) was defined as “cohesive failure”.

<Measurement of adhesive strength during heating>
A test piece was prepared in the same procedure as the normal temperature adhesive strength, and immediately after being pressure-bonded with a hand roller, the adhesive strength was measured at 70 and 90 ° C. by the same method as in the normal temperature adhesive test.

<Measurement of shear bond strength>
Hard vinyl chloride (100 mm x 25 mm) is used as the test base, applied to the 25 mm x 25 mm surface from both ends of the two bases, dried at 80 ° C for 5 minutes, and then the coated surfaces are pressed together. A test piece was obtained. After leaving it at room temperature for a predetermined number of days, the shear adhesive strength was measured by pulling under a condition of 100 mm / min with a Tensilon type tensile tester.

Production Example 1
In a 500 ml three-necked flask equipped with a stirring blade, 40.3 g of polybutylene adipate having an OH value of 56 mg KOH / g (Nipporan 4010, molecular weight 2000, manufactured by Nippon Polyurethane) and polybutylene adipate having an OH value of 111 mg KOH / g (Nipporan 4009 manufactured by Nippon Polyurethane) , Molecular weight 1000) 40.3 g was charged, and dehydration was performed under vacuum at 120 ° C. for 30 minutes. Next, the temperature was cooled to 80 ° C., 12.1 g of hexamethylene diisocyanate was added, and the reaction was performed under a nitrogen stream. After 4 hours, when the residual amount of isocyanate reached 1.1% by weight, the temperature was lowered to 50 ° C. to stop the reaction, and 200 g of acetone was added to obtain a prepolymer solution. To the obtained prepolymer solution, 3.47 g of 50% by weight aqueous solution of sodium 2- [β- (β-aminoethyl) amino-propionamide] -2 · 2-dimethylethanesulfonate and 0.90 g of triethanolamine were added. The reaction was carried out at 50 ° C. for 20 minutes, and then 130 g of water was gradually added with stirring, and the resulting polyurethane was emulsified and dispersed in water. The remaining acetone was distilled off from the obtained emulsified dispersion with an evaporator. The aqueous polyurethane dispersion a after distillation of acetone had a solid content concentration of 48.0% by weight, a median particle size of 200 nm, pH 7.8, and Mw 250,000.

Production Example 2
2- [β- (β-aminoethyl) amino-propionamide] -2 · 2-Diethylethanesulfonic acid sodium instead of ethylenediamino-N, N′-bis [(γ-propionamide) -2 · 2- An aqueous polyurethane dispersion b was obtained in the same manner as in Production Example 1 except that 6.22 g of sodium dimethylethanesulfonate was used. The solid content concentration was 49.9% by weight, the median particle size was 160 nm, the pH was 8.2, and the Mw was 293,000.

Production Example 3
An aqueous polyurethane dispersion c was obtained in the same manner as in Production Example 1 except that triethanolamine, which is an amine chain extender, was not used in Production Example 1. The solid content concentration was 49.0% by weight, the median diameter was 230 nm, the pH was 6.4, and the Mw was 222,000.

Example 1
Into a 200 ml four-necked flask equipped with a stirring blade, a dropping funnel, a cooling tube, and a thermometer insertion tube, 39.4 g (solid content: 19.2 g) of the polyurethane dispersion obtained in Production Example 1 was added, and a nitrogen stream Under stirring, 0.92 g of a 1% by weight aqueous solution of D-ascorbic acid as a reducing agent, 0.03 g of dodecyl mercaptan, 15.0 g of water, and 19.2 g of chloroprene monomer as molecular weight regulators were added. Then, it heated up at 40 degreeC and 0.075 weight% aqueous solution of potassium persulfate was dripped over 5 hours at the speed | rate of 5 ml / hr, and the polymerization reaction was performed. Further, 0.92 g of a 1% by weight aqueous solution of D-ascorbic acid was added during the reaction (3 hours after the start of polymerization). After completion of the dropwise addition of potassium persulfate, aging was performed at 40 ° C. for 1 hour to obtain a polyurethane-polychloroprene aqueous composite resin dispersion without generation of scaling. The polymerization rate of chloroprene was 84%, the median particle size was 210 nm, the pH was 7.6, and Mw was 305,000. The obtained dispersion was concentrated with an evaporator to a solid content of 50% by weight and tested for adhesion performance. The polymerization conditions are shown in Table 1, and the results are shown in Table 2. In addition, the adhesion and molecular weight were re-evaluated after 1 month of storage. Mw was 299,000, and the adhesion performance was almost the same as that immediately after preparation as shown in Table 2.

実施例２〜１０
表１に示した条件において実施例１と同じ反応器中で重合反応を行い、ポリウレタン−ポリクロロプレン水性複合樹脂分散体を得た。各々の重合率、メジアン粒径、ｐＨを表１に示す。実施例１と同様、得られた分散体を５０重量％に濃縮し、接着性能の試験を行った結果を表２に示す。

Examples 2-10
A polymerization reaction was carried out in the same reactor as in Example 1 under the conditions shown in Table 1 to obtain a polyurethane-polychloroprene aqueous composite resin dispersion. Each polymerization rate, median particle size, and pH are shown in Table 1. As in Example 1, the obtained dispersion was concentrated to 50% by weight, and the results of the adhesion performance test are shown in Table 2.

Comparative Examples 1-2
The polymerization reactions of Comparative Examples 1 and 2 were carried out under the same conditions as in Example 1 except those shown in Table 1. In Comparative Example 1, the pH of the obtained dispersion was 2.7, and scale was generated when it was concentrated to a solid content of 50% by weight and during storage. In Comparative Example 2, scale was generated during polymerization of chloroprene, during concentration, and during storage. Table 2 shows the results of the adhesion performance test.

Comparative Example 3
The polyurethane aqueous dispersion a of Production Example 1 and the polychloroprene dispersion (manufactured by Tosoh Corporation, Skyprene (registered trademark) SL-360, solid content concentration 50% by weight) were mixed at a weight ratio of 1: 1. We evaluated what we did. The adhesive strength was measured immediately after mixing. At that time, the median particle size was 220 nm, pH was 12.8, and Mw was 320,000. In addition, the adhesion and molecular weight were re-evaluated after 1 month of storage. Mw was 173,000, and the adhesive performance was lower than that immediately after mixing as shown in Table 2.

Claims (7)

Composite resin particles containing polyurethane and polychloroprene are dispersed in an aqueous medium, the weight ratio of polyurethane to polychloroprene is 99/1 to 20/80, and the pH is 7 to 10. Aqueous composite resin dispersion. The composite resin particles containing polyurethane and polychloroprene are composite resin particles obtained by radical polymerization of chloroprene monomer in an aqueous dispersion of polyurethane having a pH of 7 to 10. An aqueous composite resin dispersion. The aqueous composite resin dispersion according to claim 1 or 2, wherein the polyurethane has a particle size of 50 to 300 nm. 4. The polyurethane according to claim 1, wherein the polyurethane is a polyurethane produced by a hydrophilizing agent of a diamino compound containing a polyester polyol, diisocyanate, sulfonate group and an amine chain extender. 5. The aqueous composite resin dispersion according to Item. Diamino compounds containing a sulfonate group are sodium 2- (2-aminoethyl) aminoethanesulfonate, sodium 2- [β- (β-aminoethyl) amino-propionamide] -2 · 2-dimethylethanesulfonate , Ethylenediamino-N, N′-bis [(γ-propionamido) -2 · sodium 2-dimethylethanesulfonate], sodium 2- (2-aminoethyl) aminoethanebenzenesulfonate or ethylenediamino-N, N The aqueous composite resin dispersion according to claim 4, which is' -bis (sodium β-ethylbenzenesulfonate). The aqueous composite resin according to claim 4, wherein the amine chain extender is triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, N-methyldiisopropanolamine, or N-ethyldiisopropanolamine. Dispersion. An adhesive comprising the aqueous composite resin dispersion according to any one of claims 1 to 6.