JPH07309942A - Production of composite material - Google Patents

Abstract

PURPOSE:To produce a composite material excellent in mechanical strengths and heat resistance. CONSTITUTION:A method for producing a composite material is provided which comprises the step of bringing a clay mineral having a cation-exchange capacity of 50-200 milliequivalents/100g into contact with a swelling agent comprising a 12C or higher org. cation having alkylene and carboxyl groups to ionically combine the mineral with the swelling agent to give a composite which is swollen by a monomer at the m.p. of the monomer or higher, the step. of mixing the composite with a polyamide monomer, and the step of polymerizing the resulting mixture by heating it to a specified temp. under the catalytic action of the swelling agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a composite material having excellent mechanical strength and heat resistance. More specifically, a resin composition containing polyamide and a silicate layer constituting a clay mineral are ionically bonded. The present invention relates to a method for producing a composite material, which is bonded to each other via, and is uniformly mixed with each other, and is superior in mechanical strength to a molded product made of only resin.

[0002]

2. Description of the Related Art Conventionally, the 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.

However, when these inorganic materials are added and mixed, the bond between them and the organic polymer matrix phase in the organic polymer material is very weak, so that many problems such as embrittlement due to addition are caused. There is also a limit to the amount of addition of the inorganic material. For the purpose of strengthening the bond between the inorganic material and the polymer material, treatment of the inorganic material with a silane coupling agent is known. However, the bond between the organic polymer material and the inorganic material obtained by these methods is due to the Van der Waals bond, and is only to the extent that the compatibility between them is improved. Can't be enough.

[0004] In order to solve these problems, the applicant of the present invention has previously stated that a "polyamide-containing resin composition" composed of a polyamide-containing resin and a vermiculite flakes having an average aspect ratio of 5 or more dispersed in the polyamide. Thing "(JP-A-57-8)
3551). This composition is intended to improve the mechanical strength of an organic polymer material by incorporating a vermiculite flakes having a large aspect ratio (particle size / thickness) into a resin.

[0005]

However, although this resin composition has certainly improved the mechanical strength as compared with the conventional one, it requires mechanical crushing to obtain vermiculite flakes. A sufficient aspect ratio cannot be obtained. Moreover, since the bond strength between the mineral layer and the matrix phase is weak, it was necessary to increase the amount of addition at the expense of embrittlement in order to obtain the required strength.

Attempts have also been made to synthesize polymers such as polyamide and polystyrene between layers of clay minerals to obtain composite materials ("Polymer", 19, 759, 1).
979; "Industrial materials", 25, "3", 58, 197.
7). However, in the conventional methods, since the organic polymer chain does not sufficiently penetrate between the layers of the clay mineral, it is not possible to increase the distance between the layers, and the silicate layer and the organic polymer are evenly formed, and further, The constituent unit layer of the silicate was not dispersed in a molecular form. Further, in such a case, since the aspect ratio of the layered mineral is reduced, it has an adverse effect on improving the mechanical strength. Furthermore, since the bond between the polymer material as the matrix and the intercalation compound is not sufficient, a sufficient reinforcing effect cannot be obtained.

[0007] Further, an organic compound containing at least one amino group and having a catalytic activity for lactam polymerization is bound to clay by an ion exchange reaction. A clay is prepared by polymerizing a lactam in the presence of an organic complex. A method for producing a polyamide composite "(JP-A-51-109998) is proposed. However, the composite obtained by this method for producing a clay-polyamide composite does not have the clay in the resin separated for each crystal unit layer, and the interlayer distance between the clay layers is small, so the tensile strength is Is less than the strength of the resin as the matrix. That is, for example, it is not more than the tensile strength of nylon 6. Therefore, the composite obtained by this method has a problem of insufficient mechanical strength and heat resistance.

That is, in the method for producing the clay-polyamide composite, the clay mineral and the "organic compound containing at least one amino group and having a lactam polymerization catalyst action" are cation-exchanged to form the composite. As the organic compound, ω-aminocaproic acid, nylon salt, hexamethylenediamine, and aminoundecanoic acid are illustrated as the organic compound, and in Examples, aminocaproic acid, nylon salt, and aminoundecanoic acid are disclosed. That is,
In this method, an organic compound having a carbon chain length (carbon number) of 11 or less is used, and cation exchange is performed using "aminoundecanoic acid hydrochloride aqueous solution" containing carboxylic acid to bind clay and polymerize. A composite having a maximum interlaminar distance of about 57Å with the resulting 6-nylon is disclosed.

However, the carbon number used in this method is 1
Clay minerals exchanged with 1 or less organic compound molecules are hydrophilic, and therefore, when the drying after ion exchange is a usual method, clay mineral particles aggregate. Therefore, the subsequent mixing state with nylon becomes non-uniform, and as a result, the swelling state after polymerization becomes insufficient, and improvement in mechanical properties cannot be obtained. As a result, as shown in the examples described in the publication, the interlayer distance with the 6-nylon obtained by polymerization was about 13Å (layer spacing 6.2Å), about 20Å (layer spacing 13.1Å), about 5
Only 7Å (layer spacing 50.6Å), about 57Å at maximum, can be obtained.

Therefore, the composite obtained by the above method has an interlayer distance of 57 Å or less, so that only a tensile strength of 30 to 80% of nylon 6 can be obtained. From this, according to the above method, only "a composite having a lower tensile strength than a molded product of nylon 6 alone, but having a slightly improved tensile strength as compared with a molded product of simply adding montmorillonite to nylon 6" is obtained. I can't.

In the first place, it is conventionally said that when clay is dispersed in polyamide to form a hybrid, the mechanical strength such as tensile strength is lower than that of the original resin. The composite obtained by the method disclosed in JP-A-51-109998 aims to improve the strength reduction of this conventional composite and to approach the strength of the molded product obtained by the matrix resin alone. In other words, in other words, in each case, the mechanical strength is lower than that of the molded body obtained from the original resin alone by the compounding. As described above, the above method has a problem that it is not possible to obtain a composite having strength characteristics superior to the strength of the molded body obtained from the matrix resin alone.

Therefore, the inventors of the present invention have earnestly studied to solve the problems of the prior art as described above, and as a result of various systematic experiments, the present invention has been accomplished.

(Object of the Invention) An object of the present invention is to provide a method for producing a composite material having excellent mechanical strength and heat resistance. Another object of the present invention is to provide a method for producing a composite material having mechanical strength and heat resistance superior to those of a resin as a matrix.

With respect to the above-mentioned problems of the prior art, the present inventors have focused on the following points. That is, first, in the conventionally proposed clay-polyamide composite, when clay is dispersed in polyamide to form a hybrid, mechanical strength such as tensile strength is lower than that of the original resin.
This is because the conventionally proposed clay-polyamide composite has a weak bond between the clay layer and the polyamide and insufficient dispersibility of the clay layer, so that the tensile strength is not higher than the strength of the resin as the matrix (for example, nylon 6 The tensile strength is less than or equal to). It was also found that the constituent units of the dispersed clay layer itself are large.

As a method of solving these problems, the present inventors have made the silicate layer dispersed in a resin a minimum of constitutional units, and bond the silicate layer and the polyamide molecular chain by ionic bonding, Attention was paid to that the layer is uniformly dispersed in the resin, and that the distance between the silicate layers dispersed in the resin is 100 Å or more.

As a method for realizing this, an appropriate amount of cation exchange capacity (for example, 50 to 200 milliequivalent /
100 g) of clay minerals, coexistence of polyamide monomer and clay mineral with a substance having a very strong catalytic action for incorporating polyamide monomer molecules between layers, and appropriate expansion of the clay interlayer distance before polymerization. The present inventor has focused on the coexistence of a substance capable of forming a silicate layer and a polyamide molecular chain that are bound by an ionic bond. And, as a substance satisfying the above and, (a) a swelling agent composed of an inorganic cation such as a copper ion, a hydrogen ion, an aluminum ion, or (b) an alkylene group having 12 or more carbon atoms and a carboxyl group Attention was paid to a swelling agent composed of an organic cation (organic ammonium ion). Then, a clay mineral having the predetermined cation exchange capacity and the swelling agent are brought into contact with each other in advance to form an ionic bond between the two, and a composite having a property of being swollen by the monomer at a temperature equal to or higher than the melting temperature of the monomer is produced. Then, the composite and the polyamide monomer are mixed, and the mixture is heated to a predetermined temperature to polymerize under the catalytic action of the swelling agent, whereby a composite material having excellent mechanical strength and heat resistance is obtained. It reached, and came to complete the present invention.

[0017]

The method for producing the composite material of the present invention has a cation exchange capacity of 50 to 200 meq / m.
100 g of a clay mineral and a swelling agent composed of an organic cation (organic ammonium ion) having an alkylene group having 12 or more carbon atoms and a carboxyl group are brought into contact with each other to form an ionic bond between them, and the temperature is higher than the melting temperature of the monomer. At a temperature of swelling with a monomer having a property of swelling with a monomer, a step of mixing the composite with a polyamide monomer, and heating the mixture to a predetermined temperature to cause the catalyst action of the swelling agent. And a polymerization step of polymerizing into a.

[0018]

The mechanism by which the method for producing a composite material of the present invention exerts excellent effects is not clear yet, but it is considered as follows.

In the method for producing a composite material of the present invention, first, a clay mineral having a cation exchange capacity of 50 to 200 meq / 100 g and an organic cation having an alkylene group having 12 or more carbon atoms and a carboxyl group are prepared. The swelling agent is contacted with each other to form an ionic bond between the two, thereby forming a composite having a property of being swollen by the monomer at a temperature equal to or higher than the melting temperature of the monomer (contact step). As a result, a swelling agent can be adsorbed on the clay mineral to obtain a composite having a property of being swollen by the monomer at a temperature equal to or higher than the melting temperature of the monomer. Here, the clay mineral has a cation exchange capacity of 50.
It is a clay mineral having a large contact area with a monomer to be reacted, which is about 200 meq / 100 g. By setting the exchange capacity within the above range, the exchange and adsorption of the swelling agent composed of an inorganic cation can be sufficiently performed, and the distance between the layers of the clay mineral itself can be appropriately expanded before the polymerization. further,
By using the swelling agent composed of an organic cation having an alkylene group having a carbon number of 12 or more and a carboxyl group, the clay mineral is easily aggregated in the aqueous solution, the filtration and the water washing become easy, and the time required for the step Can be shortened.

Next, the composite obtained in the contacting step and the polyamide monomer are mixed (mixing step).

Next, the mixture obtained in the mixing step is heated to a predetermined temperature to polymerize under the catalytic action of the swelling agent (polymerization step). As a result, the silicate layer is uniformly dispersed in a resin containing polyamide in a molecular shape, the distance between the silicate layers is a predetermined value or more, and the silicate layer is one of the polymer chains of the polyamide. By forming an ionic bond with the part, a composite material having excellent mechanical strength and heat resistance can be obtained.

At this time, the swelling agent composed of an organic cation having an alkylene group having 12 or more carbon atoms and a carboxyl group has an action of incorporating polyamide monomer molecules between layers and an action of initiating ring-opening polymerization of a lactam compound. As the polymerization reaction progresses, it also has a function of incorporating the produced polymer between layers. It is considered that this is because the swelling agent has a strong force of incorporating the above-mentioned monomer between layers, so that the distance between clay layers is expanded to some extent before the polymerization, and as a result, the cohesive force between layers is reduced. Thus, it is considered that the silicate can be uniformly and molecularly dispersed for the first time by reducing the cohesive force.

As described above, by using a swelling agent having an organic cation of a carboxyl group having a carbon number within the above range, the swelling agent has a very strong effect of incorporating polyamide monomer molecules between layers and polymerizes the distance between clay layers. It is possible to obtain a composite material having excellent mechanical properties and heat resistance because it can be appropriately expanded before, and as a result, the cohesive force between layers is reduced. Furthermore, it is considered that the use of these swelling agents facilitates the aggregation of clay minerals in an aqueous solution, facilitates filtration and washing with water, and shortens the time required for the step.

[0024]

According to the method for producing a composite material of the present invention, a composite material excellent in reinforcement can be obtained by the contact step-mixing step-polymerization step, and after the polymerization, strength improving treatment such as heating and melting treatment is performed. Economical and efficient without the need to do it. Further, in the method for producing a composite material of the present invention, by using a swelling agent composed of an organic cation having an alkylene group having 12 or more carbon atoms and a carboxyl group in the contacting step, filtration and washing with water are facilitated, The time required for the process can be shortened, which is economical and efficient. Further, the composite material obtained by the method for producing a composite material of the present invention is a composite material having excellent mechanical strength and heat resistance. Further, according to the manufacturing method of the present invention, not only the above-mentioned excellent composite material can be obtained, but also the conventional composite material manufacturing step can be omitted, and the manufacturing can be performed economically and efficiently. . That is, (1) since the clay mineral having adsorbed ions according to the method of the present invention acts as a polymerization catalyst for polyamide monomers such as lactam compounds, no new catalyst addition or ring-opening reaction step for amino acid synthesis is required. . (2) Since it can be composited in the heating polymerization process, the steps of surface treatment and mixing of clay minerals can be omitted. (3) Since the silicate layer is dispersed by utilizing a chemical reaction, the method of crushing and mixing clay minerals can be simplified, and the aspect ratio does not decrease due to over-crushing. (4) The clay mineral does not deteriorate the polyamide monomer and has excellent storage stability. Therefore, the clay mineral can be stored and transported in a form of a complex with a polymer after being premixed with the monomer.

(Embodiment of the Invention) A method for manufacturing the composite material of the present invention will be described below. First, with a clay mineral having a cation exchange capacity of 50 to 200 meq / 100 g,
A composite having a property of contacting a swelling agent composed of an organic cation having an alkylene group having a carbon number of 12 or more and a carboxyl group to form an ionic bond between them and swelling with the monomer at a temperature equal to or higher than the melting temperature of the monomer Body (contact process). As a result, a swelling agent is adsorbed on the clay mineral to obtain a composite having a property of being swollen by the monomer at a temperature equal to or higher than the melting temperature of the monomer.

Here, the contacting method includes a method of immersing the clay mineral in an aqueous solution containing a desired swelling agent and then washing the clay mineral with water to remove excess ions. There is a method of contacting the cation exchange resin exchanged in step 1 with an aqueous suspension of clay mineral to perform ion exchange.

The clay mineral is a clay mineral having a large cation exchange capacity of 50 to 200 meq / 100 g and a large contact area with a monomer to be reacted. In particular,
There are smectite clay minerals such as montmorillonite, saponite, hydelite, nontronite, hectorite, and stevensite, vermiculite, halloysite, and the like, which may be natural or synthetic.

Here, the cation exchange capacity of the clay mineral used in the present invention is set to 50 to 200 meq / 100 g when the capacity exceeds 200 meq / 100 g. This is because it is difficult to obtain the composite object of the present invention. The cation exchange capacity of the clay mineral is 50 meq / 10
If the amount is less than 0 g, the exchange adsorption of the swelling agent consisting of an organic cation, which is indispensable in the production method of the present invention, cannot be sufficiently performed, and the synthesis of the composite material intended by the present invention becomes difficult. The clay mineral is preferably crushed using a mixer, a ball mill, a vibration mill, a pin mill, a jet mill, a beating machine or the like to have a desired shape and size in advance.

Further, the swelling agent has a role of expanding the layers of the clay mineral and a role of giving a force to take in the interlayer polymer into the clay mineral, and is an organic compound having an alkylene group having 12 or more carbon atoms and a carboxyl group. A swelling agent composed of one or more cations is used.

The organic cation having an alkylene group having a carbon number of 12 or more and a carboxyl group has an action of promoting the polymerization of the lactam compound, has a carbon number of 12 or more, and is X.
Is a cation represented by ⁺ -R-COOH, X ⁺ is an ammonium ion (-NH ₃ ⁺ ) or trimethylammonium ion (-N ⁺ (CH ₃ ) ₃ ), and the R group is-(CH) n-.
Is an alkylene group containing an alkyl chain represented by

[0031]

[Chemical 1]

Branch

[0033]

[Chemical 2]

A bond such as a vinylene group (HCCH--) containing is also included. Specifically, 12-aminododecanoic acid ion ^{_{(· NH 3 + · C 12}} H 22 COOH), 1
4-aminotetradecanoate ion (NH ₃ ⁺ · C ₁₃ H ₂₆
-COOH), 16-aminohexadecanoate ion (N
^{_{H 3 + · C 15 H 30}} · COOH), include 18-amino-octadecanoic acid ion ^{_{(NH 3 + · C 17 H}} 34 · COOH), using these one or two or more thereof.

The above-mentioned adsorbed clay minerals have a catalytic action for ring-opening polymerization of lactam compounds such as ε-caprolactam. Not only that, it has the ability to incorporate the polyamide produced by ring-opening polymerization of lactam and dehydration condensation of amino acid or nylon salt into the layers of clay. Therefore, the super-dispersed composite according to the present invention can be synthesized by using the clay mineral that adsorbs these ions. In the initiation of the polymerization reaction or in the polymerization reaction, the organic cation is

[0036]

[Chemical 3]

It is bonded to the polymer chain through the amide group of.
Therefore, ordinary surfactants used for lipophilicity of the surface of clay minerals cannot be used because they have no polymerization initiation action, incorporation action between polyamide layers, and binding ability with organic polymer chains.

Here, as the organic cation having a carboxyl group, any organic cation may be used as long as it satisfies the above conditions, but it is for drawing the lactam compound into the interlayer or for suppressing the evaporation of the lactam. In order to achieve this, and in order to achieve a sufficient reinforcing effect by the clay mineral, the projected area of the organic cations is preferably about 120 to 500Å ² . For example, the R group - (CH ₂₎
When n −, it corresponds to 12 ≦ n ≦ 20. In the case of n <12, or when the size of the ions is smaller than the size corresponding to this, the clay mineral is less likely to condense in the aqueous solution, which makes filtration and washing difficult, and the moisture absorption of the clay mineral. It becomes difficult to improve sex. In addition, the effect of promoting penetration of lactam molecules into the clay layer is small, which is not preferable. On the other hand, in the case of n> 20, it becomes difficult to dissolve and ion exchange becomes difficult, which is not preferable. That is, by using a swelling agent having an organic cation of a carboxyl group having a carbon number within the above range, the swelling agent has a very strong action of incorporating polyamide monomer molecules between layers, and the clay interlayer distance is appropriately adjusted before polymerization. Since it can be expanded and, as a result, the cohesive force between layers is reduced, a composite material having excellent mechanical properties and heat resistance can be obtained. Furthermore, by using these swelling agents, the clay minerals are made hydrophobic in the aqueous solution and the particles are easily aggregated, so that filtration and washing are easy, and the time required for the process is significantly shortened. It is possible to exert an effect.

The organic cation used as the swelling agent as described above has a function of incorporating polyamide monomer molecules between layers and a function of initiating ring-opening polymerization of a lactam compound,
As the polymerization reaction progresses, it also has a function of incorporating the produced polymer into the layers. The reason why only the above ions have a function of sufficiently incorporating the polymer between the layers, that is, a function of uniformly dispersing the silicate in the polymer in the polymer is not clear, but it is as follows. That is, organic cations have a large molecular size, the interlayer distance can be expanded to some extent in advance, and the interaction between the carboxyl group and the amino group in the polyamide monomer has a strong ability to incorporate these into the interlayer. Thought to be from. Thus, it is considered that the silicate can be uniformly and molecularly dispersed for the first time by reducing the cohesive force.

Next, the composite obtained in the contacting step and the polyamide monomer are mixed (mixing step).

Here, the polyamide monomer serves as a base material of the composite material and is a raw material which becomes polyamide or a mixture of polyamide and a polymer other than the polyamide after polymerization, and specifically, 6-amino-n. -Caproic acid, 12-
Amino acid compounds such as aminododecanoic acid, nylon salt compounds such as hexamethylenediamine adipate, ε-caprolactam, valerolactam, capryllactam, α
A lactam compound such as pyrrolidinone.

The mixture of the composite and the polyamide monomer can be carried out by an ordinary mixing method, specifically, mechanical mixing with an automatic mortar, a vibration mill or the like.

Next, the mixture obtained in the mixing step is heated to a predetermined temperature to polymerize under the catalytic action of the swelling agent (polymerization step). Here, this polymerization may be carried out by raising the temperature to a predetermined temperature immediately after mixing, but it is more effective if the polymer is once heated just above the melting point of the monomer and then the clay mineral is uniformly dispersed in the monomer.

The composite material obtained as described above may be used by molding by direct injection molding, heat and pressure molding or the like, or it may be mixed with another polymer such as polyamide in advance and mixed in a predetermined manner. It may be a ratio. Further, the above-mentioned polymerization reaction may be advanced in a predetermined mold to obtain a molded product. In the polyamide polymerization step, a polymerization catalyst such as phosphoric acid or water may be added.

In the present invention, a polyamide-containing resin and a silicate layer uniformly dispersed in the resin in a molecular form are formed by the above method, and the silicate layer has a thickness of 7 to 12Å.
Thus, it is possible to obtain a suitable composite material in which the distance between the silicate layers is 100 Å or more, and the silicate layer is ionically bonded to a part of the polymer chain of the polyamide. This makes it possible to obtain a composite material having excellent mechanical properties such as tensile strength and elastic modulus and heat resistance characteristics such as softening temperature and high temperature strength. This composite material has an unprecedented remarkable effect that strength and heat resistance can be remarkably improved as compared with conventional nylon.

That is, since the composite material obtained by the method for producing a composite material of the present invention has a structure in which the polyamide molecular chain is crosslinked by an ionic bond with the silicate layer,
It is difficult to deform it thermally or mechanically. Therefore, mechanical properties such as tensile strength and elastic modulus,
Excellent heat resistance such as softening temperature and high temperature strength. Further, since the layered inorganic substance is uniformly dispersed, it is excellent in dimensional stability, wear resistance, surface lubricity, water permeability and water resistance. In addition, the silicate which is an inorganic layered substance is dispersed in a unit of a molecular level thickness of about 10Å, that is, a silicate having a molecular length of about 10Å is uniformly dispersed in the resin in a molecular state. As a result, in the present invention, the strength of the composite can be improved by uniformly dispersing the layered silicate in the resin containing polyamide at the molecular level, that is, in the state of being separated for each crystal unit layer. it can. Further, the silicate layer is strongly bonded to the organic molecular chain. That is,
Since the silicate layer is ionically bonded to a part of the polymer chain of polyamide, it does not leave an adverse effect such as embrittlement which is found in a conventional inorganic composite material. The distance between the layers of the silicate dispersed in the resin is 100Å or more. In this way, by using a composite material in which a layered silicate is dispersed in a resin containing polyamide with an interlayer distance of 100Å or more, the mechanical strength and heat resistance of the composite are improved, and it is superior to ordinary nylons. Excellent strength and heat resistance can be obtained.

From the above, it is considered that the composite material excellent in mechanical strength and heat resistance could be obtained by the manufacturing method of the present invention.

The resin in the composite material obtained by the present invention is a resin containing polyamide, and is a resin composed of polyamide or a mixture of polyamide and a polymer other than polyamide.

Here, the polyamide is a general term for polymers having an acid amide bond (-CONH-), and specifically, nylon 66, nylon 6, nylon 11 and the like.

The higher the proportion of the polyamide resin, the more the effect of the present invention can be obtained. However, even if the content of the resin is 10% by weight (wt%), the effect of the present invention can be obtained. Can play.

The silicate layer imparts mechanical properties and heat resistance to the polymer material and has a thickness of 7-12.
It is a layered phyllosilicate mineral formed from the Å magnesium silicate layer or aluminum silicate layer. These silicate layers are negatively charged by isomorphic ion substitution or the like. The characteristics vary depending on the density and distribution of this negative charge,
In the present invention, the occupied area of the layer surface per negative charge is 25
It is preferably a silicate layer of about 200Å ² .

The composite material obtained by the present invention comprises a resin containing the above-mentioned polyamide and a silicate layer uniformly and molecularly dispersed in the resin.

The content of the silicate layer in the resin containing polyamide is 0.5 to 150 with respect to 100 parts by weight of the resin.
It is preferably part by weight. This is because the content is 0.5
This is because if the amount is less than the amount by weight, the silicate layer is too small and a sufficient reinforcing effect cannot be obtained. Further, the content is 15
This is because when the amount exceeds 0 part by weight, the amount of the resin component is small and only the intercalation compound powder is obtained, and it is difficult to use this as a molded body. In addition, more preferably, the content of the silicate layer is 0.5 to 2 with respect to 100 parts by weight of the resin.
5 parts by weight. Further, optimally, the content of the silicate layer is 0.5 to 10 parts by weight with respect to 100 parts by weight of the resin. This makes it possible to obtain a composite material in which a silicate layer having a distance between layers of 100 Å or more is sufficiently dispersed in a resin containing polyamide in a more uniform and molecular form, which results in tensile strength and elastic modulus. It is possible to obtain a composite material having excellent mechanical properties and heat resistance characteristics such as softening temperature and high temperature strength. This composite material has an unprecedented remarkable effect that strength and heat resistance can be remarkably improved as compared with conventional nylon.

This composite material forms an ionic bond with a silicate layer, which is a constituent unit of a negatively charged clay mineral, and a group having a positive charge that a part of polyamide in the resin has.
The positive charge, ammonium were present in the organic ion ion (-NH ₃ ⁺⁾ group, or trimethylammonium ion ^{_{(-N + (CH 3) 3}} ) group consists of at least one or more, such as a trivalent together There will be.

That is, in the composite obtained by the conventional method for producing a clay-polyamide composite, since the clay layers are not dispersed with a large inter-layer distance as in the present invention, the tensile strength as a matrix. It is less than the strength of the resin (for example, less than the tensile strength of nylon 6).
In the first place, it is said that in the prior art, when clay is dispersed in polyamide to form a hybrid, the mechanical strength such as tensile strength is lower than that of the original resin.
The present invention is not based on the idea of this conventional technique, but is made for the purpose of improving the mechanical strength and heat resistance of the molded body obtained from the original resin alone,
With the above-mentioned constitution, a material having excellent mechanical properties such as tensile strength and elastic modulus and heat resistance characteristics such as softening temperature and high temperature strength is realized. As a result, the present invention can exert a remarkable effect which has not been obtained in the past, that mechanical strength and heat resistance can be remarkably improved as compared with conventional nylon.

Examples of the present invention will be described below.

(Example 1) Montmorillonite produced in Yamagata Prefecture as a clay mineral (cation exchange capacity: 100 meq / 1
00g) was used as the swelling agent shown in Table 1 to prepare a composite, and the lactam compound was polymerized.

[0058]

[Table 1]

First, the organic cations shown in Table 1 as a swelling agent were adsorbed on montmorillonite. In this case, 10 g of montmorillonite was immersed in 1 liter of an aqueous chloride solution containing ions to be adsorbed (concentration: 1 N), and then filtration-washing with a Buchner funnel was repeated.

The ion-exchanged montmorillonite and ε-caprolactam were mixed in a predetermined ratio using a mortar, placed in an aluminum container, dried at 80 ° C. for 3 hours, and homogenized by melting ε-caprolactam. It was Put the obtained in a stainless steel sealed container,
Heat treatment was performed at 250 ° C. for 5 hours to obtain a product. This was heated at 2 ° C./min using a DSC (differential scanning calorimeter), the heat of fusion of the product was measured, and the conversion rate of the polyamide in the product was estimated. The degree of dispersion was determined by measuring the distance between silicate layers by X-ray diffraction. The results obtained are shown in Table 1.

Next, the composite materials of sample numbers 2 to 4 were molded by an injection molding machine to obtain test pieces. Using this test piece, a tensile test (JISK7113) and a heat distortion temperature were measured. The results are shown in Table 2.

[0062]

[Table 2]

For comparison, instead of the swelling agent described above,
Sodium ion (Na ⁺ ), magnesium ion (M
g ²⁺ ), and a surfactant (NH ₃ ⁺ (CH ₂ ) ₁₇ C
H ₃ ) was used, and a comparative composite was obtained in the same manner as in Example 1 above (Sample Nos. C1 to C3). The conversion of polyamide was estimated and the distance between silicate layers was measured. It was The obtained results are also shown in Table 1.

A sample (sample number: C4) prepared by kneading montmorillonite treated with aminosilane in the same proportion (montmorillonite: 10 g, nylon 6: 100 g).
And nylon 6 alone (sample number: C5) was molded in the same manner as above, and similarly subjected to a tensile test and a heat distortion temperature measurement. The obtained results are also shown in Table 2. As is clear from Tables 1 and 2, it can be seen that the composite material of this example according to the present invention is a material having excellent mechanical strength and heat resistance as compared with the comparative material.

That is, the composite material obtained in this example has improved mechanical strength and heat resistance of the composite, and has strength and heat resistance higher than that of ordinary nylon (Comparative Example: C5). I understand.

Instead of the swelling agent as in Comparative Examples C1 to C3, Na ⁺ , Mg ²⁺ , NH ₃ ⁺ (CH ₂ ) ₁₇ CH
_{In the case} of using No. ₃ , since the clay layer was not dispersed with a large interlayer distance as in this example, it was confirmed that the tensile strength was less than the strength of the resin (nylon 6) as the matrix. .

As a result, in this example, a composite material having excellent mechanical properties such as tensile strength and elastic modulus and heat resistance characteristics such as softening temperature and high temperature strength was obtained. It can be seen that the heat resistance was remarkably improved as compared with the conventional nylon.

Example 2 Vermiculite produced in China (cation exchange capacity: 180 meq / 100 g) was pulverized with a vibrating ball mill using steel balls, and then the same as in Example 1 above. - amino dodecanoic acid ion ^{_{(NH 3 + (CH 2)}} 11 COOH) is ion adsorbed as swelling agent. To 25 g of this vermiculite powder, 20 hexamethylenediamine salt of adipic acid (6.6 salt) was added.
0 g was mixed and this was treated in a nitrogen (N ₂ ) stream at 230 ° C. for 5 hours to obtain a composite material of this example according to the present invention.

In the obtained composite material, no peak corresponding to the interlayer distance was observed by the usual X-ray diffraction method (interlayer distance was 100 Å or more), and it was confirmed that the vermiculite layer was uniformly dispersed.

Example 3 A powder of montmorillonite (cation exchange capacity: 80 meq / 100 g) produced in Gunma prefecture was used in the same manner as in Example 1 to prepare 12-aminododecanoate ion (NH ₃ ⁺ (CH ₂ )). ₁₁ COOH) was used as a swelling agent for ion adsorption. 50 g of this powder was added to 12-aminododecanoate ion (NH ₃ ⁺ (CH ₂ ) ₁₁ COOH).
After mixing 50 g, the mixture was heat-treated in a nitrogen (N ₂ ) stream at 240 ° C. for 10 hours to obtain a composite material of this example according to the present invention. When the interlayer distance of the obtained composite material was confirmed in the same manner as in Example 2, it was 100 Å or more.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location C08L 77/00 KKT (72) Inventor Akane Okada Aichi-gun Aichi-gun Nagakute-cho, Nagakute-machi, Yokozoji 41 No. 1 Toyota Central Research Institute (72) Inventor Shigetoshi Sugiyama 41 Nagayote, Nagakute-cho, Aichi-gun, Aichi Prefecture

Claims (5)

[Claims] 1. A clay mineral having a cation exchange capacity of 50 to 200 meq / 100 g is brought into contact with a swelling agent composed of an organic cation having an alkylene group having 12 or more carbon atoms and a carboxyl group. Ionically bond both,
The step of contacting to obtain a composite having the property of swelling with the monomer at a temperature equal to or higher than the melting temperature of the monomer, the step of mixing the composite with the polyamide monomer, and heating the mixture to a predetermined temperature to form the swelling agent. A method for producing a composite material, which comprises a polymerization step of polymerizing under a catalytic action. 2. The swelling agent is one or a mixture of two or more of 12-aminododecanoate ion, 14-aminotetradecanoate ion, 16-aminohexadecanoate ion and 18-aminooctadecanoate ion. The method for manufacturing the composite material according to claim 1. 3. The method for producing a composite material according to claim 1, wherein the polyamide monomer is a lactam compound. 4. The method for producing a composite material according to claim 1, wherein the polyamide monomer is an amino acid. 5. The method for producing a composite material according to claim 1, wherein the polyamide monomer is a nylon salt.