JP5484680B2 - Method for producing chloroprene polymer composition - Google Patents

Description

The present invention relates to the production how the chloroprene polymer composition.

  A chloroprene-based adhesive that can be obtained by dissolving a chloroprene-based polymer in an organic solvent such as toluene, acetone, methyl ethyl ketone, and hexane together with a tackifier resin, a metal oxide, and the like has excellent adhesive performance. This chloroprene adhesive is widely used in woodwork, furniture, vehicles and other fields. Various improvements have been made on such chloroprene adhesives.

  For example, Patent Document 1 discloses, as a technique not using toluene as an organic solvent, a chloroprene adhesive composition composed of 100 parts by mass of a chlorolene rubber, 10 to 150 parts by mass of a tackifier resin, and an organic solvent not containing toluene. Has been.

  In Patent Document 2, as a technique relating to a one-pack chloroprene rubber adhesive having chloroprene rubber, alkylphenol resin, metal oxide, and organic solvent as essential components, as a formaldehyde scavenger, An ultra-low formaldehyde-dissipating one-pack chloroprene rubber adhesive containing a compound having a primary amino group and / or a secondary amino group is disclosed.

JP2003-226852A. Japanese Patent Laid-Open No. 2005-8713.

  However, the chloroprene-based adhesive has a problem that the layer is easily separated when left standing. In this regard, the inventors have focused particularly on the composition of the chloroprene polymer. Therefore, the main object of the present invention is to provide a chloroprene polymer composition having excellent layer separation resistance.

In the present invention, 100 parts by mass of a chloroprene monomer is subjected to emulsion polymerization in the presence of 0.5 to 7 parts by mass of rosin acid and / or metal salt of rosin acid until the polymerization rate becomes 55% or more. A latex aging step of heating the latex before the latex drying step at 55 to 70 ° C. for 1 to 7 hours, and a step of obtaining a latex, and a latex drying step of drying the latex at 140 to 180 ° C. The rubber obtained through the latex drying step is subjected to at least one of a rubber heating step of heating at 55 to 80 ° C. for 12 to 120 hours, purified with benzene and methanol, freeze-dried, and then 5% deuterated chloroform. When dissolved in a solution and measured for 1H-NMR spectrum, chemical shift 4.13 to 4.30 ppm peak area (a) and chemical shift The ratio of the peak area (b) of .80 to 6.50 ppm (a / b) is 0.01 / 100 to 0.65 / 100, and the chloroprene polymer composition to obtain the chloroprene polymer composition is obtained. A manufacturing method is provided .

  ADVANTAGE OF THE INVENTION According to this invention, it can be set as the chloroprene-type polymer composition excellent in delamination-proof property, having the adhesive performance as an adhesive agent.

The present invention will be described below, but the following is an example of the present invention and should not be construed as being limited thereto. The chloroprene polymer composition according to the present invention comprises chloroprene monomer and / or chloroprene monomer and 100 parts by mass of this and other monomers copolymerizable therewith, rosin acid and / or rosin acid metal. ¹ H-NMR obtained by subjecting a polymer obtained by polymerization in the presence of 0.5 to 7 parts by mass of a salt to a polymerization rate of 55% or more to heat treatment and measured in a deuterated chloroform solvent. The spectrum has a signal at least at a chemical shift of 4.13 to 4.30 ppm.

  The chloroprene-based polymer that can be used in the present invention is a homopolymer of 2-chloro-1,3-butadiene (hereinafter referred to as chloroprene), or a chloroprene monomer and another monomer copolymerizable therewith. A copolymer with the body.

  The types of other monomers copolymerizable with the chloroprene monomer are not limited, and examples thereof include esters of acrylic acid such as methyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and methyl methacrylate. , Methacrylates such as butyl methacrylate and 2-ethylhexyl methacrylate, hydroxy (meth) such as 2-hydroxyethyl (meth) acrylate, 2-hydroxymethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate Examples include acrylates, 2,3-dichloro-1,3-butadiene, 1-chloro-1,3-butadiene, butadiene, isoprene, styrene, acrylonitrile, and two or more types can be used in combination as required. It is.

  Examples of rosin acids include, but are not limited to, a single component of a resin acid such as abietic acid, dehydroabietic acid, dihydroabietic acid and pimaric acid, dihydropimaric acid, isopimaric acid and secodehydroabietic acid, or these A mixture is mentioned. In addition, fatty acids such as oleic acid, stearic acid, and octadecenoic acid may be included.

  Examples of the metal salt of rosin acid include, but are not limited to, alkali metal salts such as sodium and potassium, alkaline earth metal salts such as calcium, and ammonium salts. Preferably, it is desirable to use sodium salt or potassium salt from the viewpoint of easy handling.

  The addition amount of the rosin acid metal salt is 0.5 to 7 parts by mass, preferably 1 to 5 parts by mass with respect to 100 parts by mass of the chloroprene monomer. If the amount is less than 0.5 parts by mass, the chloroprene latex becomes unstable and the adhesion to the polymerization can etc. becomes severe, which affects the practical use. Moreover, when it exceeds 7 mass parts, the layer separation at the time of setting it as an adhesive agent will become remarkable.

  This rosin acid or rosin acid metal salt can be used as an emulsifier, but if necessary, other emulsifiers may be used in combination for the purpose of stabilizing the control of the polymerization reaction. Other emulsifiers include, for example, metal salts of aromatic sulfonic acid formalin condensate, sodium dodecylbenzene sulfonate, potassium dodecylbenzene sulfonate, sodium alkyldiphenyl ether sulfonate, potassium alkyldiphenyl ether sulfonate, polyoxyethylene alkyl ether sulfonate Examples thereof include sodium, sodium polyoxypropylene alkyl ether sulfonate, potassium polyoxyethylene alkyl ether sulfonate, potassium polyoxypropylene alkyl ether sulfonate, and the like.

  The chloroprene polymer is a chloroprene monomer, or a chloroprene monomer and other monomers copolymerizable therewith, using an emulsifier, a dispersant, a catalyst, a chain transfer agent, etc. as appropriate. It can be obtained by emulsion polymerization and adding a polymerization inhibitor when the desired polymerization rate is reached. From the polymer thus obtained, unreacted monomers can be removed by a steam flash method, a concentration method or the like.

  The polymer from which the monomer has been removed is adjusted to a neutral pH. As the neutralizing agent, an aqueous solution of an acidic substance such as acetic acid or methacrylic acid, an aqueous solution of a basic substance such as caustic soda, potassium hydroxide, or sodium carbonate can be used. The neutralized blend latex can be formed into a sheet-like or chip-like molded article after drying by a method such as freeze coagulation or salting out.

  Examples of polymerization catalysts include inorganic peroxides such as potassium persulfate, organic peroxides such as ketone peroxides, peroxyketals, hydroperoxides, dialkyl peroxides, diacyl peroxides, etc. Can do. Among these, potassium persulfate is preferably used from the viewpoint that stable polymerization can be performed. The catalyst is preferably used in an aqueous solution of 0.1 to 5% by mass.

  In order to improve the activity of the catalyst, sodium sulfite, sodium hydrogen sulfite, potassium sulfite, potassium pyrosulfite, iron oxide (II), anthraquinone β sodium sulfonate, formamidine sulfonic acid, L-ascorbic acid, hydrosulfite soda, etc. Can be added.

  The chain transfer agent is not particularly limited as long as it is generally used in the production of chloroprene polymers. For example, long-chain alkyl mercaptans such as n-dodecyl mercaptan, tert-dodecyl mercaptan, n-octyl mercaptan, etc. Dialkylxanthogen disulfides such as diisopropylxanthogen disulfide and diethylxanthogen disulfide, and known chain transfer agents such as iodoform can be used.

  The polymerization inhibitor is not particularly limited as long as it is generally used for the production of a chloroprene polymer. For example, thiodiphenylamine, diethylhydroxylamine, hydroquinone, pt-butylcatechol, 1,3,5 -Well-known polymerization inhibitors, such as trihydroxybenzene and hydroquinone methyl ether, can be used.

  The final polymerization rate is not particularly limited and can be appropriately determined. The lower limit of the final polymerization rate is preferably 60% or more, more preferably 70% or more. If the final polymerization rate is less than 60%, the adhesive strength may be lowered. The upper limit of the final polymerization rate is desirably 95% or less, more preferably 92% or less. By setting the final polymerization rate to 95% or less, the formation of a gel that is insoluble in a solvent can be suppressed, so that it can be more suitably used as an adhesive. The polymerization rate can be calculated by the following formula.

  The polymerization temperature is preferably in the range of 0 to 55 ° C. from the viewpoint of easy control of the reaction. From the viewpoint of performing the polymerization reaction more smoothly and safely, it is desirable that the lower limit value of the polymerization temperature is 10 ° C. or higher and the upper limit value is 45 ° C. or lower. And in order to prevent layer separation more effectively, it is more desirable that the lower limit of the polymerization temperature is 35 ° C. or higher and the upper limit is 45 ° C. or lower.

  An anti-aging agent can be added to the obtained chloroprene polymer. The type of anti-aging agent is not limited. For example, 2,2′-methylenebis (4-ethyl-6-t-butylphenol), 2,2′-methylenebis (4-methyl-6-t-butylphenol), 2, 6-di-t-butyl-4-methylphenol, pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], thiodiethylenebis [3- (3,5-di -T-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, N, N'-hexane-1,6-diylbis-3- (3,5-di-t-butyl-4-hydroxyphenylpropionamide), 3,5-bis (1,1-dimethylethyl) -4-hydroxyalkyl ester , Diethyl [{3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl} methyl] phosphonate, 3,3 ′, 3 ″, 5,5 ′, 5 ″ -hexa-t- Butyl-a, a ′, a ″-(mesitylene-2,4,6-triyl) tri-p-cresol, ethylenebis (oxyethylene) bis [3- (5-t-butyl-4-hydroxy-m -Tolyl) polopionate], tetraethylthiuram disulfide, tetrabutylthiuram disulfide, tetramethylthiuram monosulfide and the like.

  In addition, for the purpose of improving light resistance, an ultraviolet absorber such as benzotriazole and a light stabilizer such as hindered amine can be added to the chloroprene polymer as necessary.

In the present invention, the chloroprene polymer thus obtained is subjected to heat treatment, and in a ¹ H-NMR spectrum measured in deuterated chloroform solvent, at least a chemical shift of 4.13 to 4.30 ppm (peak A) is obtained. A chloroprene polymer composition having a signal is used.

^{The 1} H-NMR spectrum is measured by purifying the polymer obtained after the heat treatment with benzene and methanol, obtaining a freeze-dried sample, and measuring this sample using deuterated chloroform as a solvent. Peak A is a peak located at 4.13 to 4.30 ppm with reference to the peak of chloroform (7.24 ppm) in deuterated chloroform. The chloroprene polymer composition having the peak A can be used as an adhesive having excellent layer separation resistance.

  The chloroprene polymer composition having the peak A can be suitably used as an adhesive having excellent delamination resistance while having excellent adhesion performance. Although it is not certain about this mechanism of action, it is presumed that the structure represented by the following formula (1) can be obtained by performing heat treatment or the like to express the peak A. About the mechanism used as the structure of Formula (1), it is estimated that it may be because it has an alcohol group by a part of chloroprene-type monomer being hydrolyzed in reaction. In addition, “Aging Stability of Neoprene Latex”, Industrial and Engineering Chemistry, 1955, vol.47, No.1, p.171-p.176, and the like can be cited as references relating to the following formula (1). Since these are findings and are based on expectations to the last, even if a predetermined polymerization reaction proceeds due to an action other than these findings, it is of course included in the scope of the present invention. is there.

Furthermore, the area ratio (a / b) of the peak area (a) of peak A and the peak area (b) of chemical shift 3.80 to 6.50 ppm is 0.01 / 100 to 0.65 / 100. It is desirable. When the peak area (b) at a chemical shift of 3.80 to 6.50 ppm is 100, if the area (a) of peak A is less than 0.01, the effect of suppressing layer separation when an adhesive is used is sufficient. If it exceeds 0.65, the storage stability as an adhesive may be affected. The lower limit value of the area (a) of peak A is preferably 0.02 or more, and the upper limit value is preferably 0.40 or less.

The method for increasing the area ratio of peak A by applying heat treatment to the chloroprene polymer is not particularly limited. Preferably, it is desirable to carry out a step of heating the latex of the chloroprene polymer at 55 to 70 ° C. for 1 to 7 hours (latex aging step).
And it is desirable to perform the process which dries this latex at the heater temperature of 140-180 degreeC (latex drying process). More preferably, it is desirable to further perform a step (rubber heating step) of heating the rubber obtained through the latex drying step at 55 to 100 ° C. for 3 to 120 hours.

  The chloroprene polymer composition of the present invention can be dissolved in an organic solvent to form an adhesive composition. The kind of organic solvent is not limited, For example, organic solvents, such as toluene, xylene, acetone, methyl ethyl ketone, n-hexane, cyclohexane, methylcyclohexane, cyclopentane, isopropyl acetate, and ethyl acetate, can be used. You may use an organic solvent individually or in mixture of multiple types.

  Add metal oxidizing agents such as zinc white and magnesia, phenolic resins, rosin resins, tackifying resins such as coumarone resins and petroleum resins, formaldehyde catchers, and various fillers to the adhesive composition. Can do.

  As a general method for producing an adhesive, a pre-reaction resin solution prepared by dissolving an alkylphenol resin and magnesia oxide in an organic solvent and allowing to stand at 25 ° C. for 20 hours is prepared. Examples thereof include a method of dissolving a metal oxide and / or anti-aging agent kneaded with a roll.

  Of course, the chloroprene-based polymer of the present invention can be made into an adhesive by the above-described production method, but adopts a “direct dissolution method” in which preparation work such as preparation of a pre-reaction resin solution and roll kneading is omitted. Can do.

  Therefore, as a method for producing the adhesive composition according to the present invention, preferably, at least one of a metal oxide and an anti-aging agent is directly added to an organic solvent without roll kneading. A method of dissolving to obtain an adhesive composition can be employed. According to this production method, an adhesive composition having excellent layer separation resistance can be obtained easily.

  The use etc. of the adhesive composition that can be obtained by the present invention are not limited, such as paper, wood, cloth, leather, jersey, leather, rubber, plastic, earthenware, glass, mortar, cement-based material, metal, various foams, etc. It can be used for bonding various members. Furthermore, it can be used not only for the same type but also for bonding different types of members.

  Hereinafter, the present invention will be described in more detail with reference to examples. These examples do not limit the invention. Unless otherwise specified, “part” and “%” are based on mass.

[Example 1]
Polymerization of chloroprene-based polymer 110 parts of water, sodium salt of rosin acid (Longis 3R: Arakawa Chemical Co., Ltd.) 3.4 parts, 0.5 parts of potassium hydroxide, β-naphthalene sulfonic acid sodium salt (Demol NL: Kao Corporation) Manufactured) A 0.6 part aqueous emulsifier solution was charged and dissolved, and then 100 parts of chloroprene monomer and 0.1 part of n-dodecyl mercaptan were added using a reactor having an internal volume of 5 liters while stirring. Polymerization was carried out at 40 ° C. in a nitrogen atmosphere using 0.1 part by mass of potassium persulfate as a catalyst. When the final polymerization rate reached 65%, phenothiazine and 2,2-methylenebis (4-ethyl-6-tert-butylphenol) Was added to stop the polymerization, and unreacted monomers were removed under reduced pressure. This latex was heated at 60 ° C. for 3 hours (latex aging).

Preparation of chloroprene polymer rubber sheet The pH of the chloroprene polymer latex was adjusted to 7 with a 5% aqueous acetic acid solution. A chloroprene polymer rubber sheet was obtained at a drying temperature of 140 ° C. by freeze-coagulation drying.

Measurement of area ratio of peak A The obtained rubber sheet was purified with benzene and methanol and freeze-dried, dissolved in 5% deuterated chloroform solution, and JNM-GSX-400 (400 MHz, manufactured by JEOL Ltd.). FT type). In the 1H-NMR spectrum of FIG. 1, the peak area (a) of peak A at a position of 4.13 to 4.30 ppm with respect to the peak of chloroform (7.24 ppm) in deuterated chloroform, and 3.80 to 6 The ratio (a / b) of the peak at the position of 50 ppm to the peak area (b) was measured. As shown in FIG. 1, the area ratio of the peak A when as 100 3.80-6.5 0 ppm peak areas (b) (a / b) was 0.09.

The measurement conditions for nuclear magnetic resonance analysis ( ¹ H-NMR) were as follows.
・ Measurement mode: Non-decoupling ・ Flip angle: 45 degrees
・ Wait time: 4.3 seconds ・ Sample rotation speed: 0 to 12 Hz
・ Window processing: exponential function ・ Number of integration: 512
・ Measurement temperature: 30 ℃

Production of Adhesive As shown in Table 1, a resin solution was prepared by dissolving a tackifier resin and magnesium oxide in an organic solvent and reacting them at 25 ° C. for 20 hours. In this solution, a chloroprene polymer rubber sheet as shown in Table 1, an anti-aging agent (2,6-di-t-butyl-4-methylphenol, “Sumilyzer BHT”, manufactured by Sumitomo Chemical Co., Ltd.), magnesium oxide, oxidation Zinc and anti-aging agent were directly dissolved to produce an adhesive.

Evaluation of Adhesive Layer Separation Stability The adhesive solution was placed in a glass bottle, and the solution state after 4 weeks at 60 ° C. was visually observed. “◯” indicates a uniform state, and “×” indicates a state where the layer separation is severe.

Evaluation of Adhesive Viscosity Stability The solution viscosity was measured and compared with a Brooksfield viscometer immediately after placing the adhesive solution in a glass bottle and after standing at 40 ° C. for 4 weeks.

Evaluation of adhesive peel strength Adhesive is applied at 200 g / m ^{2 on} each of two canvases (25 × 150 mm). It took 30 minutes for the open time and made 5 round trips with a hand roller. Initial strength after 3 hours set time and normal strength after 10 days were measured at a tensile speed of 200 mm / min.

[Example 4]
Evaluation was performed in the same manner as in Example 1 except that the polymerization temperature was changed to 35 ° C., the polymerization rate was changed to 73%, and the latex aging was changed to 1 hour.

[Example 5]
Evaluation was performed in the same manner as in Example 1 except that Longis 3R in Example 1 was changed to 2.0 parts and Demolle NL was changed to 2.0 parts.

[Examples 7 to 11 ]
Examples 7 to 11 were evaluated under the conditions shown in Table 2, respectively. The other points were evaluated under the same conditions as in Example 1.

[Examples 14 and 15 ]
Examples 14 and 15 were evaluated under the conditions shown in Table 3, respectively. About Example 14 and 15, what changed the conditions of latex aging etc. was evaluated . Their are other points were evaluated under the same conditions as in Example 1.

[Comparative Example 1]
Evaluation was performed in the same manner as in Example 1 except that the latex aging time in Example 1 was changed to 0.5 hours and the drying temperature was changed to 120 ° C. The polymer of Comparative Example 1 is a polymer in which peak A is not confirmed.

[Comparative Example 2]
Evaluation was performed in the same manner as in Example 1 except that the latex aging time in Example 4 was changed to 0 hour and the drying temperature was changed to 120 ° C. The polymer of Comparative Example 2 is a polymer in which peak A is not confirmed.

From the above, the chloroprene polymer having at least peak A was excellent in layer separation stability after 4 weeks at 60 ° C. (Examples 1, 4 , 5 , 7-11 , 14 , 15 ). However, the chloroprene polymers having no peak A all had poor layer separation stability after 4 weeks at 60 ° C. (Comparative Examples 1 and 2).

1 is a ¹ H-NMR spectrum of a chloroprene polymer obtained in Example 1.

Claims (1)

A step of obtaining a polymer latex by emulsion polymerization of 100 parts by mass of chloroprene monomer in the presence of 0.5 to 7 parts by mass of rosin acid and / or metal salt of rosin acid until the polymerization rate becomes 55% or more. When,
A latex drying step of drying the latex at 140 to 180 ° C.,
Furthermore, a latex aging step in which the latex before the latex drying step is heated at 55 to 70 ° C. for 1 to 7 hours and a rubber heating step in which the rubber obtained through the latex drying step is heated at 55 to 80 ° C. for 12 to 120 hours. Perform at least one of the steps,
After purification with benzene and methanol and lyophilization, when dissolved in a 5% deuterated chloroform solution and measured for ¹ H-NMR spectrum, the peak area (a) of chemical shift 4.13 to 4.30 ppm and chemical shift Chloroprene-based polymer composition for obtaining a chloroprene-based polymer composition having a ratio (a / b) of 3.80 to 6.50 ppm peak area (b) of 0.01 / 100 to 0.65 / 100 Manufacturing method.