JPS6120584B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to novel latex compositions. More specifically, it has excellent wet adhesion (wet tack), which is unparalleled with existing latex adhesives, allows for arbitrary open time, and has extremely fast drying speed. , it fully satisfies the requirements for a general-purpose adhesive that can have a variety of adhesive properties by appropriately changing the selection of raw materials and their blending ratio. The present invention relates to a latex composition that provides an excellent adhesive composition and that can be blended with other latexes to adjust the texture, processability, etc. as desired. Currently, there are a wide variety of adhesives on the market, but
For example, regarding rubber adhesives, organic solvent adhesives and latex adhesives have advantages and disadvantages as shown in Table 1.

【table】

[Table] In other words, as can be seen from this table, organic solvent adhesives have a high drying speed, short oven time, high initial adhesive strength, high wet adhesive strength, and a wide variety of performance. Furthermore, they have good workability due to their properties such as drying speed, oven time, and initial adhesive strength, and are effective in improving the efficiency of bonding work, and are widely used in large quantities. However, this adhesive requires organic solvents, and environmental pollution caused by solvents has become a major social problem, and environmental management plans and Los Angeles Rule 66
In today's world, where regulations on solvents are becoming increasingly strict, they should be eliminated due to their negative effects on the human body and the environment, as well as the dangers of poisoning and fire. On the other hand, latex adhesives use large amounts of emulsifiers and large amounts of water, so they dry slowly, making it difficult to take oven time, and even if oven time can be taken, they lack adhesive strength when wet. Disadvantages: If oven time is not available, adhesive must be applied wet and pressure must be continued until dry, making it impossible to adhere water-impermeable materials such as metals, glass, and plastics. Furthermore, if the adhesive strength is low when wet, you have to wait until it dries completely, and if the drying speed is slow, organic solvent-based adhesives may be used even though water is a dispersion and is harmless to the human body. It is not possible to occupy the position as a general-purpose adhesive due to the influence of other adhesives. In other words, organic solvent-based adhesives have excellent adhesive performance, but require the use of organic solvents, while latex-based adhesives do not require the use of organic solvents and are therefore safe, but have poor adhesive performance. There is another point. To solve this problem, we have developed various properties as adhesives by blending emulsions of resin, toluene, and various other softeners and adhesives with natural rubber or rubber latex, which is currently on the market. Although attempts have been made to improve them, they do not differ significantly from conventional latex-based adhesives in terms of drying speed, oven time, initial adhesion, wet adhesion, and variety of performance. In other words, with conventional latex adhesives, high molecular weight solid rubber particles are simply dispersed in water, so even when water evaporates, the rubber particles simply fuse together to form a continuous film. It did not take on a fluid and swollen state, so it could not take much oven time and had no adhesive strength when wet. In view of the above-mentioned situation, the inventors of the present invention have intensively studied the problems of conventional latex.
per 100 diene monomer units in the solid rubber of a conjugated diene having 4 to 5 carbon atoms.
A modified high molecular weight solid rubber (A) into which 0.03 to 20 carboxyl groups or derivatives thereof have been introduced and a low molecular weight liquid rubber of a conjugated diene having 4 to 5 carbon atoms produced by solution polymerization.
(B) or a modified low molecular weight liquid rubber (B)' in which 30 carboxyl groups or derivatives thereof are introduced per 100 diene monomer units in the liquid rubber.
A rubber latex composition obtained by emulsifying a mixture of the following by a conventional method can impart various textures to dipped products, extruded products, etc., as a latex itself or as a blend of other latexes, compared to synthetic latex or natural latex. In particular, when modified rubber is used, it has remarkable processability, such as improved gel strength when wet, which reduces cracks, chips, etc., and reduces the rate of defective products. It combines the excellent adhesion performance and workability characteristic of organic solvent-based adhesives with the safety characteristic of latex-based adhesives, and is suitable for both instant bonding using oven time and wet bonding. It is also possible to adopt the method 2, which has a large particle size and requires less emulsifier (soap) during emulsification, especially when modified rubber is used, so the drying speed is faster, and it is also easier to select raw materials. We have discovered that it has even better performance, such as a diversity of adhesive performance, by being able to have a desired blending ratio,
The present invention has now been completed. In the present invention, the high molecular weight solid rubber of a conjugated diene having 4 to 5 carbon atoms used in the form of a modified high molecular weight solid rubber includes a polymer or copolymer of butadiene, isobrene, etc. Natural rubber and synthetic rubbers such as polybutadiene and polyisolene can be used. Among them, diene polymers containing 85% or more of cis-1,4 bonds obtained by solution polymerization, especially cis-polymerized in inert hydrocarbons using lithium-based catalysts or Ziegler catalysts.
Cis-1,4-polyisoprene having 95% or more of 1,4 bonds is preferably used. Any high molecular weight solid rubber may be used as long as it is solid under normal conditions, but those having an intrinsic viscosity of 1.5 to 8 are generally preferably used. Also used as these high molecular weight solid rubbers are modified high molecular weight solid rubbers in which a functional group such as a hydroxyl group, a halogen group or a carboxyl group is introduced into the molecule or at the end of the molecule. In particular, from the viewpoint of latex production, physical properties of the latex, and physical properties of products obtained from the latex, modified high molecular weight solid rubbers having carboxyl groups or derivatives thereof introduced therein as described below are preferably used. On the other hand, low molecular weight liquid rubbers of conjugated dienes having 4 to 5 carbon atoms produced by solution polymerization include polymers or copolymers that are normally liquid, such as butadiene and isoprene, and specifically, liquid polybutadiene, liquid polyisoprene, etc. can make a fist. Such a low molecular weight liquid rubber can be obtained by solution polymerization such as anionic polymerization or radical polymerization using butadiene or isoprene under specified conditions. Intrinsic viscosity is 0.04
-0.75, preferably 0.15-0.58. Note that these low molecular weight liquid rubbers into which functional groups such as hydroxyl groups, halogen groups, and carboxyl groups have been introduced may also be used. In particular, from the viewpoints of latex production, physical properties of latex, and physical properties of products manufactured from latex, a modified low molecular weight liquid rubber into which maleic anhydride is introduced is particularly preferred, as will be described later. Furthermore, in general, low molecular weight liquid cis-1,4-polyisoprene rubber polymerized using a lithium-based catalyst with a cis-1,4 bond content of 75% or more and a sharp molecular weight distribution is used as it is or modified. Often used preferably. When a tackifier-like function is desired, one rich in 1,2 bonds or 3,4 bonds may be used. The modified high molecular weight solid rubber and modified low molecular weight liquid rubber (hereinafter collectively abbreviated as modified rubbers) in the present invention are the high molecular weight solid rubber and low molecular weight liquid rubber (hereinafter collectively abbreviated as rubbers). A compound containing a carboxyl group or a derivative thereof (hereinafter abbreviated as a carboxylating agent) is added to the compound. Note that the modified rubbers include those in which the carboxyl group of the compound provided is in the form of a salt of an alkyl metal such as lithium, sodium, or potassium. The carboxylating agent used is
It does not necessarily have to have a free carboxyl group itself, but it is sufficient to have a group that can be converted into a carboxyl group (including its salts) through treatment such as hydrolysis after reacting with rubbers. . The first type of carboxylating agents are α,β-unsaturated mono- or polycarboxylic acids and their esters;
It can be expressed by the following general formula. In the formula, R ₁ and R ₂ are H, CH ₃ , C ₂ H ₅ , COOR ₅ ,
The same or different groups selected from the group consisting of CH ₂ COOR ₅ , CN, Cl and CONH ₂ , R ₃ is H, CH ₃ ,
C ₂ H ₅ , COOR ₅ or CH ₂ COOR ₅ , R ₄ is H,
CH ₃ , C ₂ H ₅ or C ₃ H ₇ , R ₅ is H, CH ₃ , C ₂ H ₅ ,
_{C3H7 , C4H9 or C6H5 .} Representative examples include acrylic acid, methacrylic acid, crotonic acid, maleic acid, tiglic acid, maleic acid monomethyl ester, maleic acid dimethyl ester, coumaric acid,
Examples include fumaric acid monomethyl ester, fumaric acid dimethyl ester, itaconic acid, itaconic acid monomethyl ester, mesaconic acid, citraconic acid, and maleic acid monoamide. The second type is α,
Anhydrides of β-unsaturated dicarboxylic acids and α,β-
It is an anhydride of unsaturated dicarboxylic acid monoamides and is represented by the following general formula. In the formula, R ₁ and R ₂ are the same or different groups selected from the group consisting of H, CH ₃ , C ₂ H ₅ , Cl and CN, R ₃ is H, CH ₃ , CONH ₂ or C ₆ H ₅ , R ₄ and R ₅ are the same or different groups selected from the group consisting of H, CH ₃ and C ₂ H ₅ . Typical examples are maleic anhydride, dimethylmaleic anhydride,
These are itaconic anhydride, citraconic anhydride, maleimide, and N-methylmaleimide. The third type is
It is an α,β-unsaturated acid chloride represented by the following general formula. In the formula, R ₁ and R ₂ are H, CH ₃ , C ₂ H ₅ , COOR ₄ ,
The same or different groups selected from the group consisting of CH ₂ COOR ₄ , CN, Cl, CONH ₂ and COCl, R ₃ is H, CH ₃ , C ₂ H ₅ , COOR ₄ , R ₄ is H, CH ₃ ,
_{C2H5 , C3H7 or C6H5 .} Typical examples include acrylic acid chloride, methacrylic acid chloride, maleic acid monochloride, maleic acid dichloride, itaconic acid chloride, and crotonic acid chloride. The fourth type is allylsuccinic acid,
It is an allyl compound containing a carboxyl group such as allylsuccinic anhydride. The fifth type does not have an unsaturated double bond as described above, but is a compound that can undergo an addition reaction to rubbers and introduce a carboxyl group into rubbers, such as thioglycolic acid, thioglycolic acid ester, azodicarboxylic acid, These include azodicarboxylic acid esters. The above carboxylating agents can be used alone or in combination, or in combination with vinyl monomers such as styrene, acrylamide, and methyl methacrylate. Among these carboxylating agents, those of the second type are preferably used, particularly maleic anhydride. Although the production of modified rubbers by reaction of rubbers with a carboxylating agent does not itself constitute a part of the present invention, it is summarized as follows. Adding a carboxylating agent to a (mixed) solution of high molecular weight solid polyisoprene, polybutadiene or natural rubber, or low molecular weight liquid polyisoprene, polybutadiene, etc. (or without a solvent),
Heat to a temperature of 50-250°C under an inert gas atmosphere. At this time, the solution may be a solution of the solvent used during the polymerization, or it may be prepared by redissolving a solid afterward. The solvents used at this time are n-butane, isopentane, n-pentane,
Hexane, bezene, toluene, xylene, etc. are preferred. For the reaction in solution, benzoyl peroxide, azobisisobutyronitrile, diisopropylbenzene hydroperoxide, cumene hydroxide, dicumyl peroxide, di-t-butyl peroxide, di-t-butyl peroxide, Common radical generating catalysts such as oxyacetate, t-butyl peroxybenzoate, di-t-butyl diperoxyphthalate, and 2,5-di-t-butyl peroxyhexane may be used.
Another method is to catalyze the carboxylating agent with high molecular weight solid rubbers and low molecular weight liquid rubbers without the use of solvents in rolls, Banbury mixers, or other kneading machines. A radical generating catalyst can also be used in this method. The best results in the present invention are achieved when modified in solution using maleic anhydride as the carboxylating agent. In this case, the radical generating catalyst is particularly preferably a catalyst that forms t-butoxy radicals, such as di-t-butyl peroxide or t-butylcumyl peroxide. In this way, carboxyl groups are introduced into high molecular weight solid rubber and low molecular weight liquid rubber. In the case of rubber, 0.03 to 20 carboxyl groups, preferably 0.3 to 8 carboxyl groups per 100 diene monomer units are appropriate, while in the case of low molecular weight liquid rubbers such as low molecular weight polyisoprene or low molecular weight polybutadiene, the same as above. As a standard, 0 to 30 pieces, preferably 0 to 6 pieces is suitable. When the amount of added carboxyl group exceeds the above range, the viscosity of the latex increases significantly, the solid content concentration decreases, the drying speed becomes slow, the tack decreases, and the water resistance of the resulting adhesive decreases. In addition, there are disadvantages such as the resulting film becomes too hard, and the stability actually decreases. Therefore, a preferred combination of a high molecular weight solid rubber and a low molecular weight liquid rubber is a combination of a modified high molecular weight solid rubber into which a carboxyl group has been introduced and a modified low molecular weight liquid rubber into which a carboxyl group has been introduced. . In addition, from the viewpoint of compatibility, it is preferable to combine materials having the same monomer unit. Among these, modified high molecular weight solid cis-1,4-polyisoprene rubber into which a carboxyl group has been introduced, low molecular weight liquid cis-1,4-polyisoprene rubber, and modified low molecular weight liquid cis-1, into which a carboxyl group has been introduced. 4- Good combination with polyisoprene rubber. The amount of carboxyl groups added can be adjusted by changing the amount of the carboxylating agent, the amount of the radical generating catalyst, the reaction temperature, etc. when the carboxylating agent is reacted. Modified high molecular weight solid rubber (A) and low molecular weight liquid rubber (B)
Or mixing with modified low molecular weight liquid rubber (B)′ is a modified high molecular weight solid rubber (carboxylation reaction) solution, low molecular weight liquid rubber, low molecular weight liquid rubber (polymerization) solution, modified low molecular weight liquid rubber or modified A method is adopted in which a low molecular weight liquid rubber or a modified low molecular weight liquid rubber arbitrarily selected from the group consisting of low molecular weight liquid rubber (carboxylation reaction) solutions is mixed. Alternatively, a mixture solution of a high molecular weight solid rubber and a low molecular weight liquid rubber may be subjected to a carboxylation reaction and then mixed in the form of a solution mixture.
There is no problem even if a third substance such as rosin, ester gum, phenol formalin resin, petroleum resin, coumaron indene resin, etc. is blended into the above-mentioned modified high molecular weight solid rubber and mixed with the low molecular weight solid rubber. Examples of the solvent used in this case include n-butane, isontane, n-pentane, hexane, benzene, toluene, and xylene. Other aliphatic and aromatic ketones such as gasoline, methyl isobutyl ketone, butyl acetate, esters, etc. may also be used. Further, a non-solvent such as methanol, ethanol or acetone may be added to the mixture solution. Further, before emulsifying these solutions, they may be washed with water to remove unreacted carboxylating agents. The solution viscosity of the thus obtained mixture of modified high molecular weight solid rubber and low molecular weight liquid rubber or modified low molecular weight liquid rubber is 5 centipoise to 1000 centipoise.
It is necessary to adjust it so that it is between poise. When the solution viscosity exceeds 1000 poise, the emulsification process (solvent removal and centrifugal concentration) causes significant precipitation of coagulum and results in a large particle size latex, which impairs stability, such as creaming phenomenon and a film on the surface of the latex. The phenomenon of acupuncture becomes visible. If it is less than 5 centipoise, the above-mentioned problem will not occur, but in this case, the solution concentration may be low or deterioration may have occurred, which is not preferable from the economical and physical property points of view. A more preferred range is between 50 centipoise and 800 poise. The appropriate polymer concentration in the solution is 3 to 95% by weight, preferably 10 to 70% by weight. The mixing ratio of modified high molecular weight solid rubber and low molecular weight liquid rubber or modified low molecular weight liquid rubber can be varied to a desired value depending on the application, and this allows for product diversity. However, in general, 1 to 95 parts by weight of modified high molecular weight rubber per 100 parts by weight of the total amount of modified high molecular weight solid rubber and low molecular weight liquid rubber or modified low molecular weight liquid rubber (in other words, low molecular weight liquid rubber or modified low molecular weight liquid rubber) Low molecular weight liquid rubber
99 to 5 parts by weight), and to increase the cohesive force, use more modified high molecular weight solid rubber, and to increase the adhesiveness, use more low molecular weight liquid rubber or modified low molecular weight liquid rubber. . From these viewpoints, a more preferable range is 20 to 90 parts by weight of low molecular weight liquid rubber or modified low molecular weight liquid rubber. However, when the modified rubbers preferably used in the present invention are used, this range also varies depending on the amount of carboxyl group addition, and can be made wider. As the emulsifier used for emulsifying the mixed solution, any commonly used emulsifier can be used, regardless of its effectiveness. However, it is important to carefully select the emulsifier depending on the application, for example when using it for adhesives or adhesives. Typical emulsifiers preferably used in the present invention include oleic acid, lauric acid, myristic acid, palmitic acid,
Fatty acid soaps such as potassium or sodium salts such as stearic acid, resin acid soaps such as potassium or sodium salts such as rosin and disproportionated rosin, sulfones such as sodium or potassium salts such as alkylbenzenesulfonic acids and alkylnaphthalenesulfonic acids. Sulfate ester soaps such as sodium salts of acid salt soaps, oleyl sulfate esters, lauryl sulfate esters, polyoxyethylene alkyl sulfates, etc.
Anionic soaps such as phosphate soaps such as hexadecyl phosphate, polyoxyethylene lauryl ether phosphate, polyoxyethylene nonyl phenyl phosphate, polyoxyethylene nonyl phenyl ether, polyethylene glycol laurate, Nonionic soaps such as polyethylene glycol oleate, aliphatic amine hydrochlorides such as dodecylamine hydrochloride, cationic stones such as alkylpyridium salts such as octyltrimethylammonium chloride, dioctyldimethylammonium chloride, benzyldimethyloctylammonium salt, and dodecylpyridium chloride. Ken and others get punched. These may be used alone or in combination. The amount of emulsifier used is 0.5 to 20 parts by weight per 100 parts by weight of the modified high molecular weight solid rubber and low molecular weight liquid rubber or modified low molecular weight liquid rubber, preferably 3 to 10 parts by weight from the viewpoint of physical properties and economy. part is sufficient. If the amount is too large, there will be no particular problem with the stability of the emulsion, but if it is used in excess, it is uneconomical and at the same time undesirable from the viewpoint of physical properties.
Although it can be carried out with less than 0.5 parts by weight, it is not preferable because the particle size becomes large and creaming and separation phenomena are observed. Emulsification is generally carried out by mixing a polymer mixture solution (oil phase) and water containing an emulsifier (aqueous phase), but in the present invention, an organic compound that forms a soap (emulsifier) is also added to the solution. Dissolve the acid,
The emulsification may be carried out using a soap production method or a phase inversion emulsification method. During emulsification, the volume ratio of the polymer mixture solution (oil phase) to water containing an emulsifier (aqueous phase) is generally in the range of 6:1 to 1:10; 5:1 in points
A range of ˜1:1 is preferred. However, when emulsifying at a volume ratio of 5:1, water may be further added to dilute the emulsification after emulsification. Generally, when the volume ratio during emulsification is in the range of 4:1 to 2:1, the stability of the emulsion is good and an emulsion with a small particle size can be obtained. Emulsification is carried out in a conventional manner using an Otzpenbach homomixer, a colloid mill, a homogenizer, a disbur mill, a line mixer, an ultrasonic emulsifier, or the like. The size of the latex particles obtained is determined during this emulsification process by the type and amount of the emulsifier, the amount of water, the strength of mixing, the composition of the modified rubber, and other factors. Suitable methods for removing the solvent from the obtained emulsion include steam distillation, vacuum distillation, vacuum steam distillation, flushing, and the like. The resulting dilute latex can be concentrated by conventional means such as centrifugal concentration, creaming, and thermal evaporation, if necessary. Even under such operations, a very stable concentrated latex can be obtained with less than 0.05% coagulation. In this way, concentrated latexes with a solids content in the range of 30 to 75% by weight can be produced economically. When the rubber latex composition of the present invention thus obtained is considered as an adhesive, it has a fast drying speed, a long open time, a large initial adhesive strength, and therefore has good workability and has good adhesive properties when wet. It has excellent adhesion properties, such as high strength and a wide variety of performance, and also has the characteristics of no safety issues since no organic solvents coexist in the product. In addition, it has a good balance of cohesive force and tack, and can be freely controlled, so it can be used for a wide range of purposes.
In addition, the characteristics shown in Table 1 can be easily amplified by mixing a small amount of a third substance, such as rosin, ester gum, phenol-formalin resin, or petroleum resin. In addition, it is preferable to introduce carboxyl groups into rubbers, since the ease of manufacturing the latex, the physical properties of the latex, and the physical properties of products made from the latex are greatly improved. In addition, in such cases, the introduced carboxyl group allows good adhesion to metals and polar substances, and also improves heat aging resistance. On the other hand, when considered as latex itself, it has merits such as being able to have various textures and being highly workable. The unique performance of the latex composition of the present invention is believed to be due to the following reasons. In other words, with conventional latex adhesives, high molecular weight, solid rubber particles are simply dispersed in water, so even when the water evaporates, the rubber particles simply fuse together to form a continuous film. , it does not take a fluid and swollen state, so it does not have an open time and does not feel tactile when wet. On the other hand, in the latex of the present invention, the low molecular weight liquid rubber or the modified low molecular weight liquid rubber and the other third substance are present in the same particle as the modified high molecular weight solid rubber or the modified high molecular weight solid rubber. Because it is mixed and dispersed in water,
Even if water remains in the process of evaporation or completely dries, the modified high-molecular weight solid rubber with high cohesive force and elasticity becomes the base, and it has good compatibility with this and is fully Low-molecular-weight liquid rubber and modified low-molecular-weight liquid rubber, which act as softeners and tackifiers that reduce viscosity and provide fluidity, or resins and solvents as third substances, are dispersed and mixed in each particle. Since it already works in this way, it is thought that it has wet adhesive strength even if the particles are not fused when dry, and that the open time can be set arbitrarily. A latex with such performance cannot be obtained by mixing a modified high molecular weight solid rubber and a low molecular weight liquid rubber or a modified low molecular weight liquid rubber latex, and as described in detail above, a modified high molecular weight solid rubber cannot be obtained. and a low molecular weight liquid rubber or a modified low molecular weight liquid rubber. The latex composition of the present invention can be widely used in the various applications mentioned above, but it can be used for natural rubber latex, IR latex, polybutadiene latex, styrene-butadiene (or isoprene) latex, Acrylonitrile-butadiene (or isoprene) latex, styrene and butadiene (or isprene) block copolymer latex,
It is also possible to use it in combination with synthetic rubber latexes such as ethylene-propylene rubber latex and ethylene-propylene terpolymer latex. It can also be used in combination with plastic emulsions such as urethane resins, acrylic resins, epoxy resins, vinyl acetate resins, ethylene-vinyl acetate copolymer resins, alkyd resins, phenolic resins, melamine resins, and unsaturated polyester resins.
Thickeners can also be added to this latex to increase its viscosity without sacrificing stability. As the thickener, methylcellulose, carboxymethylcellulose, hydroxymethylcellulose, casein, polyvinyl alcohol, polyacrylic acid or its derivatives, sodium salt or ammonium salt of polyacrylic acid, etc. can be used. Furthermore, antifreeze agents such as glycerin and ethylene glycol can also be added. Of course, softeners, fillers,
Compounding agents such as adhesives, anti-aging agents, and coloring agents can be added. Furthermore, when used as an adhesive, natural rosin, modified rosin, coumaron indene resin, terpene resin, hydrocarbon resin, cyclopentadiene resin, etc. can be added. It is also possible to carry out vulcanization by adding a vulcanizing agent, a vulcanization accelerator, a vulcanization aid, etc. as a compounding agent. EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto. Example 1 Polymerization of isoprene using Ziegler catalyst with a cis-1,4 bond content of 98% in toluene at 30°C
High molecular weight solid polyisoprene (hereinafter abbreviated as IR) with an intrinsic viscosity of 4.5 (d/g) is dissolved in toluene so that the IR concentration is 10% by weight, and 100% by weight of the solution is t-butyl peroxide
After adding 0.15 parts by weight and 1 part by weight of maleic anhydride and purging with nitrogen, the mixture was reacted at 160°C for 2 hours. This solution (A)
shall be. On the other hand, the molecular weight can be increased by polymerizing isoprene using a butyllithium catalyst in hexane.
A low molecular weight liquid polyisoprene rubber (hereinafter abbreviated as LIR) with a molecular weight of 25,000 was obtained. 10 parts by weight of toluene was added to 10 parts by weight of this LIR to obtain a 50% by weight LIR toluene solution (B). The solutions (A) and (B) were thoroughly stirred and mixed to create an apparently homogeneous solution. Add potassium oleate to 100 parts by weight of this mixed solution as rubber components (IR and LIR).
7 parts by weight per 100 parts by weight (PHR) of dissolved water
35 parts by weight was added and stirred at 900 rpm using a Pomomixer to obtain an emulsion. That is, this emulsion is an emulsion in which particles contain a mixture of carboxyl-modified IR and LIR at a ratio of 1:1. Potassium hydroxide was added to this emulsion to raise the pH, and then toluene was expelled by steam stopping to obtain a dilute latex (the pH of the dilute latex immediately after stripping was adjusted to 11.3). ). The coagulation rate at this time is 0.03%, which is extremely small. Next, this latex was centrifuged at 800 rpm to obtain a concentrated latex with a solid content concentration of 60%. At this time, no coagulum was formed at all. In addition, the mechanical stability of the obtained concentrated latex was also extremely good (the coagulation rate was measured using a Maron type measuring device at a load of 10 kg and a time of 10 minutes).
(0.1%). The obtained latex had excellent wet adhesion, an arbitrary open time, and a significantly faster drying rate than emulsion latexes obtained by emulsion polymerization. This fast drying rate is thought to be due to the large particle size and small amount of soap. Furthermore, the latex had a high gel strength when wet. The carboxyl content of the carboxyl-modified IR was 0.8 per 100 isoprene monomer units of the IR. Furthermore, by blending a small amount of this latex with natural rubber latex, soaked products such as gloves with low modulus and soft texture were created. Example 2 Polymerization of isoprene using a Ziegler catalyst with a cis-1,4 bond content of 98% and in toluene,
IR having an intrinsic viscosity of 4 (d/g) at 30°C was dissolved in toluene to prepare a toluene solution of 8% IR. Di-t-butyl peroxide and various carboxylating agents were added to this solution in the amounts shown in Table 2, and the mixture was reacted at 170° C. for 2 hours under a nitrogen atmosphere.
In this way, a modified IR solution (A) was obtained. On the other hand, the molecular weight can be increased by polymerizing isoprene using a butyllithium catalyst in hexane.
Obtained LIR(B) of 47,000. 5 parts by weight of LIR(B) and
After stirring and mixing 100 parts by weight uniformly, oleic acid was added to this mixed solution in an amount of 7 parts by weight based on the rubber components (100 parts by weight of IR and LIR) and mixed well. This solution was emulsified with 40 parts by weight of an aqueous solution prepared by dissolving 1.5 times the amount of potassium hydroxide needed to neutralize the oleic acid in a homomixer at maximum rotation (11,000 rpm) for 3 minutes. did. In this way, while producing soap, an emulsion with a relatively small particle size was obtained. That is, these emulsions are a mixture of carboxyl-introduced IR and LIR at a ratio of 8:5. Potassium hydroxide was further added to these emulsions to raise the pH, and then the toluene was removed by steam stripping to obtain a dilute latex. At this time, the pH immediately after stripping was all set to PH10.8 or higher. The coagulation rate at this time was 0.01 to 0.1%, which was good. This latex was then concentrated to a solid content of 50-75% using a centrifuge at 800 rpm. The mechanical stability of the obtained concentrated latex was also good;
It had excellent adhesive strength when wet, had an arbitrary open time, and had a fast drying rate, so it could be used as a general-purpose adhesive. Furthermore, this latex can be blended with natural rubber latex or other synthetic rubber latex to produce soft-textured dipped products or extruded products, or even when blended with other synthetic latexes, processability is significantly improved and modulus can be controlled. It was something.

【table】

[Table] Example 3 High molecular weight solid rubber polybutadiene with 95% cis-1,4 bonds obtained by solution polymerization ([η] = 3.7) 100
400 parts by weight of low molecular weight liquid polybutadiene obtained by solution polymerization with a molecular weight of 6000 was dissolved in 200 parts by weight of penzene. Add this mixed solution to
-0.15 parts by weight of butyl peroxide and 8 parts by weight of maleic anhydride were added and reacted at 170°C for 2 hours.
The number of added carboxyl groups was 1.2 per diene monomer unit of the polybutadiene mixture.
Polyoxyethylene nonyl phenyl ether phosphate was added to 100 parts by weight of this solution in an amount of 7 parts by weight based on 100 parts by weight of the modified polybutadiene mixture, mixed well, and dissolved. To this, 40 parts by weight of water was gradually added and emulsified using a homomixer (900 rpm). This emulsion has a pH of
After adjusting to 8.5, benzene was removed by vacuum steam stripping. The resulting dilute latex was concentrated to 62% using a centrifuge. Concentrated very stably. This latex had excellent wet tack, an arbitrary open time, a fast drying rate, and excellent gel strength when wet. Example 4 Isoprene was polymerized using a Ziegler catalyst to produce IR with a cis-1,4 bond content of 98% and an intrinsic viscosity of 3.5 (d/g) at 30°C in toluene at an IR concentration of 12% by weight.
0.15 parts by weight of t-butylcumyl peroxide and 2 parts by weight of maleic anhydride were added to 100 parts by weight of the solution, and the mixture was reacted at 160° C. for 2 hours under a nitrogen atmosphere. The solution thus obtained is referred to as (A). On the other hand, LIR with a molecular weight of 30,000 was obtained by polymerizing isoprene in hexane using a butyllithium catalyst. this
A toluene solution (B) of LIR was obtained by dissolving 4 parts by weight of LIR in 4 parts by weight of toluene. The solutions (A) and (B) were thoroughly stirred and mixed to prepare a uniform mixed solution. 100 parts by weight of this mixed solution,
A latex was obtained by emulsifying 40 parts by weight of a mixed soap aqueous solution of 3 PHR of sodium dodecylbenzenesulfonate and 4 PHR of potassium oleate under the same conditions as in Example 1. This latex has excellent tack and cohesion, and when blended with natural latex or synthetic rubber latex, it was found to be highly effective in controlling texture and processability.

Claims (1)

[Claims] 1 Modified high molecular weight solid rubber (A) obtained by introducing 0.03 to 20 carboxyl groups or derivatives thereof per 100 diene monomer units in the solid rubber into a high molecular weight solid rubber of a conjugated diene having 4 to 5 carbon atoms. and a low molecular weight liquid rubber (B) of a conjugated diene having 4 to 5 carbon atoms by solution polymerization, or a modified rubber in which up to 30 carboxyl groups or derivatives thereof are introduced per 100 diene monomer units in the liquid rubber. A novel rubber latex composition obtained by emulsifying a mixture consisting of molecular weight liquid rubber B'.