TWI681978B - Carboxyl polyacrylate (acm) elastomer capable of controlling curing time - Google Patents

Abstract

A carboxyl polyacrylate (ACM) elastomer capable of controlling curing time is provided by emulsion or suspension polymerization of acrylics monomers and monomers with carboxyl function groups. The carboxyl polyacrylate (ACM) elastomer includes over 50% acrylic rubber and 0.5~20% monomers with carboxyl function groups for cross linking in the acrylic rubber. Such a carboxyl polyacrylate (ACM) elastomer can be processed within moderate period without the operation under lower temperature or using the vulcanization agent of slow reaction rate.

Description

Carboxyl polyacrylate elastomer capable of controlling vulcanization time

The present invention relates to the field of a Carboxyl Polyacrylate (ACM) rubber/elastomer, in particular to a carboxy polyacrylate elastomer with controlled vulcanization time.

Carboxyl polyacrylate elastomer is a polymer that can be further vulcanized to form a specific function. In the vulcanization process of general carboxypolyacrylate elastomers, one or several vulcanizing agents are usually used to react with the carboxyl (-COOH) functional group on the molecular chain of the carboxypolyacrylate elastomer, so that Carboxypolyacrylate elastomers have better physical properties, such as better compressibility or heat resistance. However, the use of the vulcanizing agent also causes some problems. For example, when the vulcanizing agent is added during the mixing process and the vulcanizing agent is well dispersed, there is a tendency to pre-cure, making the carboxypolyacrylate elastomer too hard or Scorch phenomenon that is too tough and difficult to process. Or, the carboxyl polyacrylate elastomer has poor fluidity and cannot be completely molded or filled in the mold. The disadvantages mentioned above can be improved by lowering the vulcanization temperature during the vulcanization process, but it will lead to disadvantages such as increased processing time and reduced production. Therefore, how to balance vulcanization time, output and processing of elastomers is a problem that needs to be solved when using carboxyl polyacrylate elastomers.

A carboxypolyacrylate elastomer with controllable vulcanization time is provided here, which is composed of monomers with cross-functional groups mixed in different proportions. The carboxypolyacrylate elastomer thus formed can be used in a suitable vulcanization process in the subsequent vulcanization process. Complete processing within time without having to reduce operating temperature or use slower vulcanizing agents. This advantage has great advantages for injection molding and foaming processing methods.

Provided herein is a carboxypolyacrylate elastomer with controllable vulcanization time, which includes at least 50% w/w (weight ratio) acrylic rubber, and the acrylic rubber contains 0.5% to 20% The monomer having a carboxyl functional group that can be used for bridging reaction can be vulcanized without reducing the bridging reaction temperature.

According to the above, a carboxyl polyacrylate elastomer with controllable vulcanization time includes at least 50% of acrylic rubber and the acrylic rubber contains 0.5% to 20% of carboxyl groups with bridging reaction available for bridging reaction A functional group monomer, wherein the carboxyacrylic acid ester elastomer capable of controlling the vulcanization time is formed by polymerizing acrylic monomers and at least one monomer having a carboxyl functional group by emulsion polymerization or suspension polymerization .

Preferably, the chemical formula of the acrylate monomer is expressed as:

Among them, R is one of alkyl, alkoxyalkyl and cyanoalkyl.

Preferably, the structures of the alkyl group, the alkoxy group and the cyanoalkyl group are first-, second-, or third-carbon types, respectively, the alkyl group contains 2 to 18 carbon atoms, and the alkoxy group is Contains 2 to 10 carbon atoms, and the cyanoalkyl group contains 2 to 20 carbon atoms.

Preferably, the monomer having a carboxyl functional group is an unsaturated acid (unsaturated acids) or a fumarate derivative (fumarate), wherein the unsaturated acid is acrylic acid or methacrylic acid ), maleic acid/maleic acid or itaconic acid; the fumaric acid derivative is monoethyl fumarate or monobutyl fumarate (monobutyl fumarate) fumarate).

Preferably, the monomer having a carboxyl functional group includes two or more different monomers.

The carboxyl polyacrylate elastic system of the present invention is formed by polymerizing acrylic monomers and monomers that can provide bridging functional groups, wherein the content of acrylic monomers used in the polymerization is much larger than that of bridging groups. Monomer content.

其中，R可以是烷基(alkyl)、烷氧基(alkoxyalkyl)、氰烷基(cyanoalkyl)三者之一。 烷基、烷氧基或氰烷基的結構可以是一級、二級、三級碳的型態，其中，烷基可以是含有2到18個碳原子；烷氧基可以是含有2到10個碳原子；氰烷基可以是含有2到20個碳原子。以下舉例但不限地，烷基類例如丙烯酸乙酯(ethyl acrylate)、丙烯酸正丁酯(n-butyl acrylate)等等；烷氧基類例如甲氧基丙烯酸甲酯(methoxymethyl acrylate)、2-甲氧基丙烯酸乙酯(2-methoxyethyl acrylate)；氰烷基類例如氰丁基丙烯酸酯(cyanobutyl acrylate)、氰己基丙烯酸酯(cyanohexyl acrylate)等等。 The chemical formula of acrylic monomers can be expressed as:

Wherein, R may be one of alkyl, alkoxyalkyl, and cyanoalkyl. The structure of the alkyl, alkoxy or cyanoalkyl group can be in the form of primary, secondary and tertiary carbons, wherein the alkyl group can contain 2 to 18 carbon atoms; the alkoxy group can contain 2 to 10 carbon atoms Carbon atoms; cyanoalkyl groups may contain 2 to 20 carbon atoms. The following examples, but not limited to, alkyls such as ethyl acrylate (ethyl acrylate), n-butyl acrylate (n-butyl acrylate), etc.; alkoxy groups such as methoxymethyl acrylate (methoxymethyl acrylate), 2- 2-methoxyethyl acrylate; cyanoalkyls such as cyanobutyl acrylate, cyanohexyl acrylate, etc.

The monomer that can provide a bridging group, preferably the monomer that provides a carboxyl functional group as a functional group may be an unsaturated acid or a fumarate derivative. The following examples, but not limited to, unsaturated acids such as acrylic acid, methacrylic acid, maleic acid/maleic acid, itaconic acid, etc.; Horse acid derivatives such as monoethyl fumarate, monobutyl fumarate and the like.

Secondly, the carboxyl polyacrylate elastomer of the present invention can be formed by emulsification polymerization or suspension polymerization. The polymerization process can be carried out using batch reactors or continuous reactors. In addition to the air or oxygen in the reactor. Secondly, the temperature of the polymerization reaction is about -10°C to 95°C, preferably about 5°C to 50°C). Furthermore, the polymerization to form the carboxypolyacrylate elastomer of the present invention includes the use of catalysts and surfactants. Catalysts usually use chemicals that can generate free radicals. For emulsion polymerization, for example, organic peroxide or hydroperoxide alone, or organic peroxide or hydroperoxide They are matched with redox catalysts. For example, but not limited to, organic peroxides such as benzoyl peroxide; hydroperoxides such as hydrogen peroxide to methane (paramethane hydroperoxide); redox catalysts such as persulfate salts (persulfate salts), Sodium persulfate, potassium persulfate, etc. In addition, The surfactant used in the emulsification polymerization reaction may be an anionic, cationic or nonionic surfactant. The preferred ones of the present invention are sodium salts, potassium salts, sulfonates of fatty acids. In addition, the water used in the emulsion polymerization reaction is usually adjusted to an appropriate pH value with inorganic salts, and the pH value can also be adjusted with acids or bases.

After that, the emulsion after the emulsification polymerization reaction can be subjected to demulsification to obtain the carboxypolyacrylate elastomer of the present invention. In the first embodiment of the present invention, multivalent metal salts such as calcium chloride (CaCl ₂ ), magnesium sulfate (MgSO ₄ ), aluminum sulfate (Al ₂ (SO ₄ ) ₃ ), aluminum chloride ( AlCl ₃ ) and so on to destroy the stability of the emulsion after the emulsion polymerization reaction. In the second embodiment of the present invention, the addition of alcohols, such as methanol, is used to destroy the stability of the emulsion after the emulsion polymerization reaction. In the third embodiment of the present invention, the carboxypolyacrylate elastomer in the emulsion is made into blocks by freezing, and these lumps can be washed and dried to obtain the carboxypolyacrylate elastomer of the present invention . Furthermore, the Mooney viscosity (ML ₁₊₄ ) measured by the carboxypolyacrylate elastomer of the present invention at a temperature of 100° C. using a large rotor is approximately between 20 and 100.

The following examples illustrate the preparation of the carboxypolyacrylate elastomer of the present invention by emulsion polymerization. Four practical examples are included in Table 1. In each case, the same but different proportions of acrylic monomers are used with different compositions and different proportions of monomers that can provide bridging functional groups. When mixing, the acrylic monomer, the monomer containing a carboxyl (-COOH) functional group, and half of the water are first placed in a container. Put another half of the water in another container to dissolve Polyoxyethylene Alcohol Ether and Sodium Lauryl sulfate, then mix the solution in the two containers and stir continuously. Next, about 7% of the above mixture was put into the reactor, followed by adding sodium formaldehyde sulfoxylate and hydrogen peroxide to methane (Paramethane hydroperoxide) and other catalysts to start polymerization. It should be noted that the air or oxygen in the reactor must be removed before the emulsification polymerization reaction is carried out. The reactor should have a good tightness and keep stirring. In addition, the reaction temperature is controlled at 5°C to 40°C, preferably 20°C to 35°C; the reaction time is about 4 hours, and the remaining mixture is stably put into the reactor for about 4 hours. After that, the emulsion after the polymerization reaction can be de-emulsified with sodium sulfate (Na ₂ SO ₄ ) at a concentration of 20% by weight at a temperature of about 80°C. The obtained carboxypolyacrylate elastomer was washed four times with water. The product obtained after drying (generally also called raw rubber) was measured at 100°C using a large rotor for Mooney viscosity (Mooney viscosity). ; ML ₁₊₄ ) are also listed in Table 1.

The carboxypolyacrylate elastomer of the present invention obtained by the above method can be compounded with two-roll mills, a vulcanizing agent, and other required chemicals. For example, common types of vulcanizing agents include first- or second-level polyamines, such as: hexamethylene diamine carbamate or (6-aminohexyl) carbamic acid (hexamethylenediamine carbamate), N, N'-biscinnamaldehyde-1,6-hexanediamine (N,N'-dicinnamylidene-1,6-hexanediamine) and so on. another, Chemicals that can be mixed with carboxyl polyacrylate elastomers also contain antioxidants, such as phenols and amines, such as hindered phenols, phosphated phenols, Phenyl β-naphthylamine (-phenyl-β-naphthylamine) and so on. In addition, in general mixing, examples, but not limited, may also include a part of fillers (plastics), plasticizers (plasticizers), waxes (waxes), oils (oils), etc.

The following is a bridge system that uses the four carboxy polyacrylate elastomers obtained in Table 1 and adds polyamine to the two-roll mill operation. Other reinforcing materials (such as carbon black) and additives can also be used Join to improve the physical properties and processability of raw rubber, mixing and mixing as shown in Table 2:

Among them, phr is expressed as the percentage content of additives in rubber (or resin), (parts per hundreds of rubber (or resin)), for example: stearic acid 20phr represents 100g or kg and other mass units of rubber (or Resin) Add stearic acid 20g or kg and other mass units.

Continued, the curing temperature of carboxy polyacrylate elastomer is about 120~230℃, and the time of bridging changes with the bridging temperature. Carboxypolyacrylate of Table 2 after mixing The elastomer was heated with a hot steel plate at 180°C for ten minutes, and was bridged when the test piece was produced. The measured physical properties of the test pieces are listed in Table 3.

According to Table 3, the scorch time is generally used to determine the vulcanization time. Scorch refers to the early vulcanization phenomenon generated during rubber processing. During the scorch time, the cross-linking has not yet started, and the compound has good fluidity. This stage determines the processing safety of the compound. At the end of this stage, the compound begins to crosslink and lose fluidity. Therefore, the scorch time is the time taken for the process of converting plastic rubber into elastic rubber or hard rubber. Therefore, the carboxypolyacrylate elastomer in this case can control the vulcanization time.

In addition, the carboxyl polyacrylate elastomer which can control the vulcanization time in this case can be composed of monomers with bridge functional groups mixed in different proportions. Four practical examples are included in Table 4. In each case, the same but different ratios of acrylic monomers are used with two or more components to provide bridge functional monomers.

Similar to Table 1, the carboxypolyacrylate elastomer of the present invention obtained in Table 4 can be kneaded by the roller with the vulcanizing agent and other required chemicals, and the kneading method will not be repeated here. The following are the bridge systems using the four carboxy polyacrylate elastomers obtained in Table 4 with polyamine added to the roller operation. Other reinforcements (such as carbon black) and additives can also be added to enhance the physical properties and processability of raw rubber , Mix and match as shown in Table 5.

The temperature of the vulcanized bridging (cure) of the carboxypolyacrylate elastomer obtained in Table 5 can still be about 120-230°C, and the bridging time varies with the bridging temperature. Carboxylic acid of Table 4 after mixing The base polyacrylate elastomer was heated with a hot steel plate at 180°C for ten minutes, and was bridged when the test piece was produced. The measured physical properties of the test pieces are listed in Table 6.

It can be obtained from the data in Table 6 that when the present invention uses two or more components in different proportions to provide bridging functional groups in combination with acrylics monomers, the vulcanization time can be controlled. Carboxyl polyacrylate elastomer.

Although the present invention has been disclosed as above with examples, it is not intended to limit the present invention. Those with ordinary knowledge in the technical field to which the present invention belongs can make various modifications and retouching without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be deemed as defined by the scope of the attached patent application.

Claims (4)

A carboxyl polyacrylate elastomer capable of controlling vulcanization time, including at least 50% by weight of acrylic rubber, and the acrylic rubber contains 0.5% to 20% by weight of carboxyl groups for bridging reaction A functional group monomer, wherein the carboxy-acrylic acid ester elastomer capable of controlling the vulcanization time is formed by emulsion polymerization of acrylic monomers and at least two monomers having a carboxyl functional group, wherein the at least 2. The monomer having a carboxyl functional group is maleic acid and methacrylic acid, maleic acid and itaconic acid, methacrylic acid and monobutyl fumarate, or acrylic acid, itaconic acid and methacrylic acid. The carboxy polyacrylate elastomer with controllable vulcanization time according to claim 1, wherein the chemical formula of the acrylate monomer is expressed as:

Among them, R is one of alkyl, alkoxyalkyl and cyanoalkyl. The carboxypolyacrylate elastomer with controllable vulcanization time according to claim 2, wherein the structures of the alkyl group, the alkoxy group and the cyanoalkyl group are in the form of primary, secondary or tertiary carbon, respectively. The carboxy polyacrylate elastomer with controllable vulcanization time according to claim 2, wherein the alkyl group contains 2 to 18 carbon atoms, the alkoxy group contains 2 to 10 carbon atoms, and the cyanide The base contains 2 to 20 carbon atoms.