JP4730983B2 - Chloroprene latex, production method thereof and adhesive composition using the same - Google Patents

Description

【００５５】
【表２】

【００５６】
【表３】

【００５７】
（注１）ＰＶＡ；ＵＭＲ−２０Ｈ けん化度７９モル％ 重合度３８０（ユニチカ社製）
（注２）ＰＶＡ；ＵＭＲ−３０Ｈ けん化度７９モル％ 重合度５４０（ユニチカ社製）
（注３）ＰＶＡ；ＵＭＲ−２０Ｍ けん化度６５モル％ 重合度３８０（ユニチカ社製）
（注４）ＰＶＡ；Ｂ−０５ けん化度８８モル％ 重合度５５０（電気化学工業社製）
（注５）３−メチル−３−メトキシ−１−ブタノール：ソルフィット（クラレ社製）
（注６）テルペン変性フェノール樹脂エマルジョン；タマノールＥ−１００（荒川化学工業社製）
（注７）亜鉛華；ＡＺ−ＳＷ（大崎工業社製）
【００５８】
以上の実施例と比較例の比較より、本発明のクロロプレンラテックスは接着強性能、特に耐熱性と耐水性のバランスにすぐれ、更に耐候変色性にも優れていることが明かであり、布、合板など木材接着、紙材、合成樹脂、鋼板などの接着に特に好適なクロロプレンラテックス接着剤組成物と、その製造方法を提供することが出来る。
【００５９】
【発明の効果】
以上説明した様に、本発明によれば、耐熱性と耐水性等の接着物性のバランスに優れ、更に耐候変色性に優れたクロロプレンラテックスとその製造方法、それを用いた有機溶剤を含まない水系の接着剤組成物を提供することが出来る。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a chloroprene latex effective as an adhesive, a production method thereof, and an adhesive composition using the same. More particularly, the present invention relates to a chloroprene latex that is excellent in the balance of adhesion performance and weather resistance discoloration and is suitable as an aqueous contact adhesive, a production method thereof, and an adhesive composition using the same.
[0002]
[Prior art]
Conventionally, the solvent type is the mainstream of adhesives based on polychloroprene. However, in recent years, solvent-based adhesives have been increasingly demanded to be solvent-free due to problems such as toxicity, fire hazard, and environmental pollution caused by organic solvents during production and use.
[0003]
As a method for removing the solvent, it is considered effective to replace the solvent-type adhesive with a latex adhesive, and studies on latex adhesives using various polymers have been actively conducted.
[0004]
Of these, the chloroprene latex adhesive is applied to both of the adherends to be joined, and these adhesive layers are bonded together after drying, thereby exhibiting high adhesive force immediately after the bonding. These characteristics are expected to be used as water-based contact adhesiveness, but the balance of contact performance, heat resistance, water resistance and other adhesive performance is not always satisfactory, and weather discoloration is regarded as a problem. In some cases, this improvement has been a challenge.
[0005]
For example, Japanese Patent Publication No. 52-13983 discloses a method for producing a chloroprene latex adhesive in which chloroprene is polymerized in the presence of an α, β unsaturated carboxylic acid, polyvinyl alcohol and a chain transfer agent. However, the polyvinyl alcohol used in the examples of these publications has a saponification degree of 87 to 89 mol% and a polymerization degree of 500 to 600, and the latex produced thereby has a balance of adhesion performance and weather resistance discoloration. It was not always satisfactory.
[0006]
Also, similar production methods are disclosed in JP-A-6-287360, JP-A-6-336579, and JP-A-7-165804, but any of the polyvinyl alcohols used here is saponified. The degree was 88 mol%, and it was not possible to solve the problems related to the balance of adhesion performance and weather resistance.
[0007]
[Problems to be solved by the invention]
The present invention solves such problems of the prior art, and provides a chloroprene latex excellent in the balance of adhesive properties, weather resistance discoloration and its production method, and an aqueous adhesive containing no organic solvent using the same. A composition is provided.
[0008]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventors have achieved a balance of adhesive properties such as initial adhesiveness, heat resistance, and water resistance by using polyvinyl alcohol having a specific saponification degree. It has been found that a chloroprene latex excellent in weather resistance discoloration and an adhesive composition using the same can be obtained, and the present invention has been completed.
[0009]
That is, the present invention relates to chloroprene or chloroprene and 2,3-dichloro-1,3-butadiene, 1-chloro-1,3-butadiene, butadiene, isoprene, styrene, acrylonitrile, esters of acrylic acid, esters of methacrylic acid 100 parts by weight of a monomer copolymerizable with chloroprene selected from 0.5 to 10 parts by weight of ethylenically unsaturated carboxylic acid, 0.5 to 10 parts of polyvinyl alcohol having a saponification degree of 60 mol% or more and less than 70 mol%. It is a chloroprene latex obtained by polymerization in the presence of parts by weight.
[0010]
The chloroprene latex preferably has a gel content of 10 to 70% by weight.
It is preferable that the yellow index after the dry film of the chloroprene latex is subjected to an irradiation test for 10 hours with a xenon weather meter is less than 50.
[0011]
The present invention also provides chloroprene or chloroprene and 2,3-dichloro-1,3-butadiene, 1-chloro-1,3-butadiene, butadiene, isoprene, styrene, acrylonitrile, esters of acrylic acid, and esters of methacrylic acid. 100 parts by weight of a monomer copolymerizable with chloroprene selected from 0.5 to 10 parts by weight of ethylenically unsaturated carboxylic acid, 0.5 to 10 parts of polyvinyl alcohol having a saponification degree of 60 mol% or more and less than 70 mol%. A method for producing a chloroprene latex, wherein polymerization is performed in the presence of parts by weight.
Moreover, this invention is an adhesive composition characterized by containing said chloroprene latex and tackifying resin.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
The present invention relates to 100 parts by weight of chloroprene or a monomer copolymerizable with chloroprene and chloroprene and 0.5 to 10 parts by weight of an ethylenically unsaturated carboxylic acid, polyvinyl alcohol having a saponification degree of 60 mol% or more and less than 70 mol%. The present invention relates to a chloroprene latex obtained by polymerization in the presence of 0.5 to 10 parts by weight, a production method thereof, and an adhesive composition using the same.
[0014]
The chloroprene latex in the present invention is typically a copolymer of chloroprene (representing 2-chloro-1,3-butadiene) and an ethylenically unsaturated carboxylic acid homopolymer, or copolymerizable with chloroprene. Also included are copolymers obtained by further copolymerizing one or more of these monomers.
[0015]
Examples of the monomer copolymerizable with chloroprene in the present invention include 2,3-dichloro-1,3-butadiene, 1-chloro-1,3-butadiene, butadiene, isoprene, styrene, acrylonitrile, and esters of acrylic acid. And esters of methacrylic acid, and two or more of them may be used as necessary. These monomers are used in the range of 0 to 50% by weight based on chloroprene.
[0016]
Specific examples of the ethylenically unsaturated carboxylic acid in the present invention include acrylic acid, methacrylic acid, crotonic acid, fumaric acid, maleic acid, citraconic acid, glutaconic acid, etc., and these may be used alone or in combination of two or more. Can also be used.
[0017]
The amount of the ethylenically unsaturated carboxylic acid added depends on the type and molecular weight of the unsaturated carboxylic acid, but the present invention is 0.5 to 100 parts by weight per 100 parts by weight of the monomer copolymerizable with chloroprene or chloroprene and chloroprene. The addition of 10 parts by weight is preferred, more preferably 1 to 5 parts by weight. When the addition amount of the ethylenically unsaturated carboxylic acid is less than 0.5 parts by weight, the adhesive strength and heat resistance are lowered, and the stability of the latex is also lowered. On the other hand, when it exceeds 10 parts by weight, the storage stability of the latex is poor.
[0018]
The polyvinyl alcohol in the present invention must have a saponification degree of 60 to 85 mol%. When the saponification degree of polyvinyl alcohol exceeds 85 mol%, water resistance is lowered and weather discoloration resistance is inferior. On the other hand, when the amount is less than 60 mol%, a problem occurs in the polymerization control of chloroprene, and a stable latex cannot be obtained. More preferably, the saponification degree of polyvinyl alcohol is 70 to 82 mol%, and by using this, the polymerization operation can be performed more stably.
[0019]
The polyvinyl alcohol in the present invention has a saponification degree of 60 to 85 mol% and a polymerization degree of preferably 200 to 3000, more preferably a polymerization degree of 200 to 700.
[0020]
The addition amount of polyvinyl alcohol in the present invention is preferably 0.5 to 10 parts by weight per 100 parts by weight of chloroprene or chloroprene and a monomer copolymerizable with chloroprene. More preferably, it is 2-5 weight part, More preferably, it is 2.5-4.5 weight part. When the addition amount of polyvinyl alcohol is less than 0.5 parts by weight, the emulsifying power is not sufficient, and the occurrence of aggregates frequently occurs during the polymerization reaction. On the other hand, if the amount exceeds 10 parts by weight, thickening occurs during the polymerization reaction, hindering stirring and abnormal heat generation, making stable polymerization difficult and water resistance lowering.
[0021]
The chloroprene latex in the present invention preferably has a toluene-insoluble gel content in the range of 10 to 70% by weight, more preferably 20 to 60% by weight, and still more preferably 30 to 50% by weight. . When the gel content is less than 10% by weight, the adhesive strength, particularly heat resistance, tends to decrease. On the other hand, when the gel content exceeds 70% by weight, the contact property and initial adhesiveness are lowered, and the water resistance tends to be lowered.
[0022]
In order to control the gel content of chloroprene latex, it is possible to control (1) the use and amount of chain transfer agent, (2) the polymerization temperature and (3) the polymerization rate.
[0023]
First, the chain transfer agent is not particularly limited as long as it is generally used in the production of chloroprene latex. For example, long chain alkyl mercaptans such as n-dodecyl mercaptan and tert-dodecyl mercaptan, diisopropyl xanthogen disulfide and diethyl Known alkyl chain transfer agents such as dialkylxanthogen disulfides such as xanthogen disulfide and iodoform can be used.
[0029]
The method for producing a chloroprene latex of the present invention comprises 100 parts by weight of the above chloroprene or a monomer copolymerizable with chloroprene and chloroprene and 0.5 to 10 parts by weight of an ethylenically unsaturated carboxylic acid with a saponification degree of 60 mol%. The polymerization is carried out in the presence of 0.5 to 10 parts by weight of polyvinyl alcohol having a concentration of less than 70 mol% .
[0030]
The polymerization temperature is preferably in the range of 0 to 55 ° C. for polymerization control. In order to perform the polymerization reaction more smoothly and safely, the polymerization temperature is preferably 30 to 50 ° C.
[0031]
The final polymerization rate is preferably 80% by weight or more, more preferably 90% by weight or more. If the final polymerization rate is less than 80% by weight, the gel content is often not increased to the target level, which is not preferable.
[0032]
In the present invention, the solid content concentration of the chloroprene latex is preferably in the range of 40 to 65% by weight, more preferably in the range of 50 to 60% by weight. By setting a higher solid content concentration, the drying speed is fast and the latex has an excellent initial adhesiveness. The solid content concentration can be adjusted by the ratio of the monomer and water during polymerization, but can be adjusted by concentration after polymerization.
[0033]
The chloroprene latex obtained in the present invention can be used as an adhesive by adding a tackifier resin or other components as an additive to form an adhesive composition. As additives, basic substances such as diethanolamine can be added as pH adjusters, surfactants such as aliphatic alkanolamides, rosin acid ester resins, terpene phenol resins, coumarone-indene resins, aliphatic hydrocarbon resins, Adhesive resins such as aromatic resins, metal oxides such as zinc oxide, inorganic fillers such as calcium carbonate and silica, plasticizers and softeners such as dibutyl phthalate and process oil, and various anti-aging agents are optionally added. be able to. In particular, it is preferable to use a tackifying resin for the purpose of controlling the adhesion performance, and it is particularly easy to add an emulsified resin.
[0034]
The amount of the additive contained in the adhesive composition of the present invention is preferably 5 to 100 parts by weight for the tackifier resin and 0 to 50 parts by weight for the other components with respect to 100 parts by weight of the chloroprene latex.
Moreover, it is preferable that the solid content concentration in an adhesive composition exists in the range of 40 to 70 weight%, More preferably, it is the range of 50 to 70 weight%.
[0035]
The chloroprene latex adhesive composition obtained by the present invention is suitable for bonding of the same kind or different kinds of paper, wood, cloth, leather, leather, rubber, plastic, foam, earthenware, glass, ceramic, metal and the like. is there. In addition, with regard to the construction method at the time of bonding, brush coating, trowel coating, spray coating, roll coater coating and the like are possible.
[0036]
【Example】
EXAMPLES The present invention will be specifically described below with reference to examples, but these examples do not limit the present invention. In addition, the part and% in the following description are shown on a weight basis.
[0037]
Reference example 1
Using a reactor having an internal volume of 3 liters, 94 parts of water and 3.5 parts of polyvinyl alcohol (Unitika UMR-20H saponification degree 79 mol%, polymerization degree 380) were added and heated (60 ° C) under nitrogen flow. did. After cooling this aqueous solution to near room temperature, 97 parts of chloroprene monomer, 3 parts of methacrylic acid, and 0.3 part of octyl mercaptan were added thereto. While maintaining this at 40 ° C., polymerization was carried out using sodium sulfite and potassium persulfate as initiators to obtain a latex. The final polymerization rate was 98%.
[0038]
Next, 20% diethanolamine aqueous solution was added to this chloroprene latex to adjust the pH to 7, and then 3 parts of a 20% aqueous solution of 1: 2 molar fatty acid alkanolamide (Diamond Simoyaloc Chemical Co., Ltd.) was added. . Further, the water was evaporated under reduced pressure and concentration was performed, and the solid content concentration was adjusted to 55%.
[0039]
Next, the following measurements were performed on this chloroprene latex.
[Gel content measurement]
A latex sample was freeze-dried and precisely weighed. The dried sample was dissolved in toluene (prepared to 0.6%), and the gel was separated using a centrifuge and further using a 200-mesh wire mesh. The gel was air-dried and then dried in an atmosphere at 110 ° C. for 1 hour, and weighed precisely to obtain B.
The gel content was calculated according to the following formula.
[0040]
[Expression 1]
Gel content = (B / A) × 100 (%)
The results are shown in Table 1.
[0041]
[Normal peel strength]
With the formulation shown in Table 1, latex, tackifier resin, and zinc white were added and mixed in this order to prepare an adhesive composition.
Next, 200 g (solid content) / m ² of the adhesive composition was applied to each of two canvases (25 × 150 mm) with a brush, dried for 3 minutes in an atmosphere of 100 ° C., and allowed to stand at room temperature for 1 minute. The surfaces were bonded together and pressed with a hand roller.
Five days after pressing, the 80 ° peel strength was measured with a tensile tester at a tension rate of 50 mm / min.
[0042]
[High temperature peel strength]
With the formulation shown in Table 1, latex, tackifier resin, and zinc white were added and mixed in this order to prepare an adhesive composition.
Next, 200 g (solid content) / m ² of the adhesive composition was applied to each of two canvases (25 × 150 mm) with a brush, dried for 3 minutes in an atmosphere of 100 ° C., and allowed to stand at room temperature for 1 minute. The surfaces were bonded together and pressed with a hand roller.
Five days after pressing, the condition was adjusted for 20 minutes in an 80 ° C. atmosphere, and the 80 ° peel strength was measured with a tensile tester at a tension rate of 50 mm / min in an 80 ° C. atmosphere.
[0043]
[Water resistance]
With the formulation shown in Table 1, latex, tackifier resin, and zinc white were added and mixed in this order to prepare an adhesive composition.
Next, 200 g (solid content) / m ² of the adhesive composition was applied to each of two canvases (25 × 150 mm) with a brush, dried for 3 minutes in an atmosphere of 100 ° C., and allowed to stand at room temperature for 1 minute. The surfaces were bonded together and pressed with a hand roller.
Five days after pressing, it was immersed in water for two days, and the 180 ° peel strength was measured with a tensile tester at a pulling speed of 50 mm / min.
[0044]
(Weather resistance)
The raw latex was applied onto white EVA foam with a brush at 200 g (solid content) / m ² and dried at room temperature for 24 hours. Using a xenon weather meter (manufactured by Suga Test Instruments Co., Ltd.), irradiance of 390 W / m ² , wavelength range of 300 to 700 nm, black panel temperature of 63 ° C., relative humidity of 50 ± 5 (% / RH), conditions without water spraying The color change with time was examined. As for the color tone, the yellow index was measured with a Σ80 color measuring system (manufactured by Nippon Denshoku Industries Co., Ltd.).
[0045]
Reference example 2
In Reference Example 1 , the type of polyvinyl alcohol was UMR-30H (degree of saponification 79 mol%, degree of polymerization 540), and polymerization was carried out in the same manner as in Reference Example 1 . The gel content, adhesive properties and weathering discoloration were measured in the same manner as in Reference Example 1, and the results are shown in Table 1.
[0046]
Example 1
In Reference Example 1 , the type of polyvinyl alcohol was UMR-20M (saponification degree 65 mol%, polymerization degree 380), and polymerization was performed in the same manner as in Reference Example 1 . Compared with Reference Example 1, it was difficult to control the reaction during polymerization. The gel content, adhesive properties and weathering discoloration were measured in the same manner as in Reference Example 1, and the results are shown in Table 1.
[0047]
Reference example 3
In Reference Example 1 , polymerization was carried out in the same manner as in Reference Example 1 except that the amount of octyl mercaptan added was 0.25 part. The gel content, adhesive properties and weathering discoloration were measured in the same manner as in Reference Example 1, and the results are shown in Table 2.
[0048]
Reference example 4
In Reference Example 1 , polymerization was performed in the same manner as in Reference Example 1 with the addition amount of octyl mercaptan being 0.35 part. The gel content, adhesive properties and weathering discoloration were measured in the same manner as in Reference Example 1, and the results are shown in Table 2.
[0051]
Comparative Example 1
In Reference Example 1 , polymerization was carried out in the same manner as in Reference Example 1 , using Denkapoval B-05 (degree of saponification 88 mol%, degree of polymerization 550) as the type of polyvinyl alcohol.
The gel content, adhesive properties and weathering discoloration were measured in the same manner as in Reference Example 1, and the results are shown in Table 3.
[0052]
Comparative Example 2
In Comparative Example 1, polymerization was carried out in the same manner as in Reference Example 1 with the addition amount of octyl mercaptan being 0.25 parts. The gel content, adhesive properties and weathering discoloration were measured in the same manner as in Reference Example 1, and the results are shown in Table 3.
[0053]
Comparative Example 3
In Comparative Example 1, the polymerization was performed in the same manner as in Reference Example 1 with the addition amount of octyl mercaptan being 0.35 part. The gel content, adhesive properties and weathering discoloration were measured in the same manner as in Reference Example 1, and the results are shown in Table 3.
[0054]
[Table 1]

[0055]
[Table 2]

[0056]
[Table 3]

[0057]
(Note 1) PVA; UMR-20H Degree of saponification 79 mol% Degree of polymerization 380 (manufactured by Unitika)
(Note 2) PVA: UMR-30H Degree of saponification 79 mol% Degree of polymerization 540 (manufactured by Unitika)
(Note 3) PVA; UMR-20M degree of saponification 65 mol% degree of polymerization 380 (manufactured by Unitika)
(Note 4) PVA; B-05 degree of saponification 88 mol% degree of polymerization 550 (manufactured by Denki Kagaku Kogyo)
(Note 5) 3-Methyl-3-methoxy-1-butanol: Solfit (manufactured by Kuraray Co., Ltd.)
(Note 6) Terpene-modified phenol resin emulsion; Tamanol E-100 (Arakawa Chemical Industries)
(Note 7) Zinc Hana; AZ-SW (Osaki Kogyo Co., Ltd.)
[0058]
From the comparison of the above examples and comparative examples, it is clear that the chloroprene latex of the present invention has excellent adhesion strength, particularly a balance between heat resistance and water resistance, and also excellent weather discoloration, and cloth, plywood. It is possible to provide a chloroprene latex adhesive composition particularly suitable for bonding wood, paper, synthetic resin, steel plate, and the like, and a method for producing the same.
[0059]
【The invention's effect】
As described above, according to the present invention, a chloroprene latex excellent in the balance of adhesive properties such as heat resistance and water resistance, and further excellent in weathering discoloration, its production method, and an aqueous system containing no organic solvent using the same. The adhesive composition can be provided.

Claims (5)

Co-used with chloroprene or chloroprene and chloroprene selected from 2,3-dichloro-1,3-butadiene, 1-chloro-1,3-butadiene, butadiene, isoprene, styrene, acrylonitrile, esters of acrylic acid, esters of methacrylic acid 100 parts by weight of polymerizable monomer and 0.5 to 10 parts by weight of ethylenically unsaturated carboxylic acid in the presence of 0.5 to 10 parts by weight of polyvinyl alcohol having a saponification degree of 60 mol% or more and less than 70 mol%. Chloroprene latex obtained by polymerization.   The chloroprene latex according to claim 1, wherein the gel content of the chloroprene latex is 10 to 70% by weight.   The chloroprene latex according to claim 1 or 2, wherein the dried film of chloroprene latex has a yellow index of less than 50 after an irradiation test for 10 hours with a xenon weather meter. Co-used with chloroprene or chloroprene and chloroprene selected from 2,3-dichloro-1,3-butadiene, 1-chloro-1,3-butadiene, butadiene, isoprene, styrene, acrylonitrile, esters of acrylic acid, esters of methacrylic acid 100 parts by weight of polymerizable monomer and 0.5 to 10 parts by weight of ethylenically unsaturated carboxylic acid in the presence of 0.5 to 10 parts by weight of polyvinyl alcohol having a saponification degree of 60 mol% or more and less than 70 mol% A method for producing a chloroprene latex characterized by polymerization.   An adhesive composition comprising the chloroprene latex according to claim 1 and a tackifying resin.