JPS63221125A - Production of composite material - Google Patents

Abstract

PURPOSE:To obtain a composite material excellent in mechanical strengths and heat resistance, by mixing a specified composite obtained from a clay mineral and a swelling agent with a monomer comprising a diamine compound and a dicarboxylic ester compound and polymerizing the mixture. CONSTITUTION:A laminar clay mineral of a cation exchange capacity of 50-2,000meq/100g is contacted with a swelling agent to obtain a composite which swells in a molten state of the following polyamide monomer. The obtained composite is mixed with a polyamide monomer comprising a diamine compound and a dicarboxylic ester compound. This mixture is polymerized by heating to a predetermined temperature to obtain the purpose composite material. A process for performing this contact comprises, for example, immersing said clay mineral in an aqueous solution containing the desired swelling agent or contacting a cation exchange resin previously exchanged with a desired swelling agent with an aqueous solution of said clay mineral.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is a composite material having excellent mechanical strength and heat resistance, and more specifically, a silicate layer comprising a resin composition containing polyamide and a clay mineral. The present invention relates to a method for manufacturing a composite material in which these materials are uniformly mixed and bonded to each other through ionic bonds.

[Conventional technology]

Addition and mixing of inorganic materials such as calcium carbonate, clay minerals, and mica have been studied for the purpose of improving the mechanical properties of organic polymer materials.

As one of these, the applicant has developed a composite material in which a resin containing polyamide and a silicate layer constituting clay minerals are bonded to each other through ionic bonds and are uniformly mixed (patent application). No. 1983-217396). This composite material has a structure in which polyamide molecular chains are cross-linked by ionic bonds with layered clay minerals, so it has excellent mechanical strength and heat resistance. The method for manufacturing this composite material is to bring the clay mineral and the swelling agent into contact, mix it with a polyamide monomer, and heat the mixture to polymerize the polyamide monomer. Examples include amino acids, suiron salt, and lactams.

However, when using nylon salts as polyamide monomers, depending on the combination with swelling agents.

It was found that it was not possible to obtain a material in which the silicate layer constituting the clay mineral was sufficiently dispersed. That is, the nylon salt replaces the swelling agent, and this substitution reaction prevents the silicate layers from expanding during polymerization.

Furthermore, when using an interfacial polycondensation method, which is one of the methods for synthesizing polyamide, a reaction occurs in which the ammonium salt produced during one reaction replaces the swelling agent.

It has also been found that it is not possible to obtain a composite material in which the silicate layer is uniformly distributed.

[Purpose of the invention]

Therefore, the present inventors conducted intensive research to solve the problems of the conventional techniques as described above, and as a result of various systematic experiments, they came up with the present invention.

An object of the present invention is to provide a method for producing a composite material in which a silicate layer constituting a clay mineral is sufficiently dispersed and has excellent mechanical strength and heat resistance.

[Structure of the invention]

The method for producing a composite material of the present invention has a cation exchange capacity of 5
A contacting step of contacting a layered clay mineral of 0 to 200 mm/100 g with a swelling agent to obtain a composite having a property of swelling in the molten state of the polyamide monomer;
It is characterized by comprising a mixing step of mixing the composite with a polyamide monomer consisting of a diamine compound and a dicarboxylic acid ester compound, and a polymerization step of heating the mixture to a predetermined temperature and polymerizing it.

Below, the configuration of the present invention will be explained in more detail.

First, the cation exchange capacity is 50 to 200 meq/10
0 g of layered clay mineral is brought into contact with a swelling agent (contact step). As a result, the swelling agent is adsorbed onto the clay mineral to obtain a composite having the property of swelling in the molten state of the polyamide monomer. That is, a composite having a property in which the interlayers of clay mineral layers (silicate layers) expand in the polymerization step described below is obtained.

Here, this contact method is a method of immersing the clay mineral in an aqueous solution containing a desired swelling agent, or a method of contacting a cation exchange resin exchanged with a predetermined swelling agent with an aqueous solution of the clay mineral. There are methods such as ion exchange. In addition, in the ion-exchange method, the ion-exchanged clay mineral may be used while containing a small amount of water, or the water may be removed by freeze-drying.

Clay minerals provide mechanical properties and heat resistance to polymeric materials, and are layered phyllosilicate minerals formed from a magnesium silicate layer or an aluminum silicate layer with a thickness of 7 to 12 people. These clay minerals are negatively charged due to isomorphic ion substitution and the like. Although the characteristics vary depending on the density and distribution of the negative charges, in the present invention, it is preferable to use a layered clay mineral in which the area occupied by each negative charge on the surface of the layer is 25 to 200. Specifically, these clay minerals include montmorillonite and saponite.

beidellite, nontronite, hectorite.

Examples include smectite clay minerals such as stipunsite, vermiculite, and halloysite, and they may be natural or synthetic.

In addition, clay minerals have a cation exchange capacity of 50 to 200
It has a large contact area with the monomer to be reacted. Here, the reason why the cation exchange capacity is set to 50 to 200 meq/100g is because when the capacity exceeds 200 meq/100g, the binding force between the eyebrows of the mineral is strong, which is the object of the present invention. This is because it becomes difficult to obtain a composite material.

Also, you win 50 millimeters! When the amount is less than 100 g, the exchange adsorption of the swelling agent consisting of organic cations or inorganic cations, which is essential in the present invention, cannot be carried out sufficiently.

In addition, clay minerals can be processed using mixers, ball mills, vibration mills,
It is preferable to crush it using a bottle mill, a jet mill, a beater, etc., and give it a desired shape and size in advance.

In addition, the swelling agent has the role of widening the glabella and making it easier for the polyamide monomer and the solvent used in the reaction to enter the glabella by replacing exchangeable cations present between the layers of the clay mineral. Examples of the swelling agent include compounds having organic cations such as ammonium compound ions (RaN''), sulfonium compound ions (R, 3S''), and phosphonium compound ions (R4, P'') (R is Alkyl groups, allyl groups, aryl groups, hydrogen, but not all hydrogen).

Next, the composite obtained by the contacting step.

A polyamide monomer consisting of a diamine compound and a dicarboxylic acid ester compound is mixed (mixing step).

Here, the polyamide monomer is a raw material that becomes polyamide after polymerization, and forms the base of the composite material.

Examples of the diamine compound include bexamethylene diamine, tetramethylene diamine, and the like.

One or more of them are used. Further, examples of the dicarboxylic acid ester compound include adipic acid dimethyl ester, sebacic acid dimethyl ester, etc., and one or more types thereof are used.

Further, the above composite and the polyamide monomer are mixed by mechanical mixing using an automatic mortar, vibrating mill, or the like.

This mixing results in a mixture in which the composite is dispersed in the polyamide monomer.

Next, the mixture obtained in the mixing step is heated to a predetermined temperature and polymerized (polymerization step).

This polymerization may be carried out by raising the temperature to a predetermined temperature immediately after mixing, but it is possible to carry out the polymerization by heating it to a predetermined temperature immediately after mixing.
It is effective to disperse clay minerals in monomers.

Further, the above polymerization is carried out by adding a polymerization initiator, heat, light, etc. to the mixture. Also.

The type of polymerization may be any polymerization method such as heptad condensation polymerization, radical polymerization, cationic polymerization, anionic polymerization, coordination polymerization, etc., and conditions suitable for each of the nine polymerization types may be selected.

Further, the heating temperature for polymerization is desirably 100 to 300°C. 1
This is because if the temperature is lower than 00°C, the removal of the produced alcohol will not proceed efficiently, and if the temperature exceeds 300°C, loss due to evaporation of the monomer and decomposition of the polymer will occur.

The composite material obtained as above consists of polyamide,
It consists of a layered clay mineral uniformly dispersed in the polyamide, and the clay mineral has a layer thickness of 7 to 12 layers and an interlayer distance of 3.
It is 0 Å or more. More specifically, it is thought that N (silicate layer) of clay mineral is incorporated into the molecular chain of polyamide through ionic bonding. There is. Furthermore, the composite material can be molded by an injection molding method, a hot pressure molding method, or the like. Alternatively, the molded article may be obtained by allowing the above polymerization reaction to proceed in a predetermined mold. Further, in the polyamide polymerization step, a polymerization catalyst such as phosphoric acid or water may be further added.

Further, glass fiber or the like may be mixed with the above composite material, or may be added to other polymers as a reinforcing agent. When added to other polymers, the higher the polyamide content, the better the composite material can be obtained, but the content may be as low as 10-t%.

The content of clay mineral in the polyamide or polyamide and other polymer is preferably 0.5 to 150 parts by weight based on 100 parts by weight of the polyamide or polyamide and other polymer. This means that the content is 0
．． If it is less than 5 parts by weight.

This is because sufficient properties such as reinforcement cannot be obtained because the clay mineral content is too small. On the other hand, if the amount exceeds 150 parts by weight, only a clay mineral powder is obtained due to the small amount of resin components such as polyamide, which is difficult to use as a molded product.

[Operation and effect of the invention]

By the method for producing a composite material of the present invention, a composite material in which a silicate layer constituting a clay mineral is sufficiently dispersed in polyamide can be obtained. This is considered to be due to the following reasons.

The carboxylic acid ester compound used as the polyamide monomer suppresses the diamine compound, which is one of the polyamide monomers, from turning into a diammonium salt during the reaction. If a diammonium salt is formed, this diammonium salt acts on the clay mineral treated with a swelling agent, replacing the organic cations present between the silicate layers, and reducing the swelling property of the clay mineral. I'll make you lose it. Therefore, even if the polymerization step is performed in this state, the glabella of the silicate layer does not widen, and the silicate layer cannot be uniformly dispersed in the polyamide. In the method of the present invention, the use of a carboxylic acid ester compound suppresses the formation of diammonium salts without causing the clay mineral to lose its swelling properties.

It is possible to obtain a composite material in which a silicate layer of clay mineral is uniformly dispersed in the polyamide.

In addition, according to the method of the present invention, nylon 66, nylon 610, which has been difficult to synthesize in the past. -1-Iron 46
etc. and clay minerals can be easily synthesized.

Furthermore, even if an interfacial polycondensation method is used in the ninth polymerization step, a composite material in which the silicate layer is uniformly dispersed in the resin can be produced.

Furthermore, a composite material obtained by the method of the present invention is as follows.

It is a composite material with excellent mechanical strength and heat resistance.

The manufacturing method of the present invention not only has the above-mentioned effects, but also can omit the conventional composite material manufacturing process. That is, (1)
Since the clay mineral adsorbed with ions by the method of the present invention acts as a polymerization catalyst for polyamide monomers, there is no need to add a new catalyst or to perform a ring-opening reaction step for amino acid synthesis.

(2) Since composite formation is possible through the polymerization process, the steps of surface treatment and mixing of minerals can be omitted. (3) Since the silicate layer is dispersed using a chemical reaction, the method of crushing and mixing clay minerals can be simplified, and there is no reduction in aspect ratio due to excessive crushing. (4) Clay minerals do not alter the properties of polyamide monomers or polymers and have excellent storage stability, so they can be stored and transported either as a pre-mix with monomers or in the form of a composite with polymers after one polymerization.

〔Example〕

The present invention will be explained in detail below.

Example 1 Montmorillonite as a clay mineral (cation exchange capacity 1
00 milliequivalent/100g, F! Thickness = 9.8 people) 10 parts by weight were dispersed in distilled water using a mixer. To this was added 2.2 parts by weight of 12-aminolaurate hydrochloride as a swelling agent, and the mixture was stirred with a mixer. This ion-exchanged the montmorillonite, which was collected by suction filtration and washed with distilled water. Furthermore, freeze-dry it.

Made into powder.

Next, 174.20 parts by weight of hexamethylene diamine, 116.21 parts by weight of dimethyl adipate, and 14.5 parts by weight (dry weight) of the above-mentioned ion-exchanged montmorillonite were placed in a separable glass flask, and the mixture was heated with nitrogen gas. Replaced. This mixture was heated at 150°C for 3 hours with stirring.
Methanol produced by heating for a period of time was removed. The mixture was further heated at 250° C. for 2 hours in a nitrogen stream to obtain a product.

The obtained product was determined to be 5 by IR spectrum and elemental analysis.
．． It was confirmed that it was nylon 66 containing 2 parts by weight of clay mineral. Furthermore, it was confirmed by powder X-ray diffraction that the interlayer distance between the silicate layers of montmorillonite was 100 Å or more. In addition, when a test piece was molded by injection molding and its mechanical properties were evaluated, the 1 bending strength was 152 MP.
a, the flexural modulus was 4.06 GPa.

Comparative Example 1 A comparative example using hexamethylene diamine and adipic acid as polyamide monomers is shown.

146 parts by weight of adipic acid was dissolved in 1000 parts by weight of anhydrous methanol, and 116 parts by weight of hexamethylene diamine was added thereto with stirring. The precipitated crystals were passed through the mouth, washed with anhydrous cold ethanol, and then vacuum-dried at room temperature overnight. As a result, the yield was 254 parts by weight (97%), and the melting point was 1.
Nylon 66 salt was produced at 96-197°C.

Montmorillonite 5 was ion-exchanged with 100 parts by weight of the nylon 66 salt thus obtained in the same manner as in Example 1.
Parts by weight were mixed using a mortar and placed in a separable glass flask. The inside of the flask was replaced with nitrogen gas, and 21
Heat treatment was performed at 5°C for 2 hours and at 270°C for 1 hour to obtain a product.

Powder X-ray diffraction of this product revealed that the distance between the silicate layers of montmorillonite was 214.

In other words, it was found that the silicate layer was not sufficiently dispersed. When the mechanical properties of the injection molded test piece were evaluated, the bending strength was 130 MPa, and the bending modulus was 2.9 GPa.

Example 2 Montmorillonite was ion-exchanged in the same manner as in Example 1, except that 16-aminohexadecano hydrochloride was used as the swelling agent.

5.0 parts by weight of this ion-exchanged montmorillonite and 60.07 parts by weight of hexamethylene diamine.

46.52 parts by weight of diethyl adipic acid were placed in a separable glass flask and heated in a nitrogen stream at 150°C for 2 hours and at 250°C for 1 hour to obtain a product.

The obtained product is 1. No peak corresponding to the distance between the eyebrows is observed by ordinary X-ray diffraction method (interlayer distance is 100 Å or more)
It was confirmed that the silicate layer of montmorillonite was uniformly dispersed in nylon 66.

Example 3 Montmorillonite produced in Yamagata Prefecture (cation exchange capacity 120 mm/100 g) was treated with 12-aminolauric acid cation (NH3 (CHz) + +C) in the same manner as in Example 1.
00H) was adsorbed.

116.21 parts by weight of hexamethylene diamine and 230.31 parts by weight of dimethyl sebacate were added to 5 parts by weight of the ion-adsorbed montmorillonite, and the mixture was placed in a separable glass flask.

This mixture was heat-treated at 180° C. for 2 hours in a nitrogen stream to remove generated methanol. Then in a nitrogen stream 2
A product was obtained by heat treatment at 30° C. for 1 hour.

In this product, it was confirmed by X-ray diffraction that the glabella of the silicate of montmorillonite spread over 100 Å.

Claims (1)

[Claims] A contacting step of contacting a layered clay mineral with a cation exchange capacity of 50 to 200 milliequivalents/100 g with a swelling agent to obtain a composite having a property of swelling in the molten state of the polyamide monomer; A method for producing a composite material, comprising a mixing step of mixing a polyamide monomer consisting of a diamine compound and a dicarboxylic acid ester compound, and a polymerization step of heating the mixture to a predetermined temperature and polymerizing it.