JPS6335653B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a heat-resistant resin, more specifically a heat-resistant resin made of acrylonitrile, acrylic esters, methacrylic esters, acrylamides, and an organic acid having a polymerizable unsaturated bond. The present invention relates to a method for producing a heat-resistant resin. As a result of various studies on resins obtained mainly by polymerizing vinyl monomers, the present inventors have developed a resin that has extremely excellent heat resistance by copolymerizing acrylonitrile as the main component with several types of vinyl monomers. He discovered that it was possible to create polymers and completed this invention. This will be explained in detail below. The present inventors have discovered that when acrylonitrile and acrylic esters, methacrylic esters, acrylamides, or methacrylic acid are bonded adjacent to each other in a polymer, a heat-resistant polymer skeleton is formed by heat treatment. As a result of detailed research into the possibility of formation, we discovered that a heat-resistant heterocyclic structure is formed. When acrylonitrile and acrylic esters or methacrylic esters are adjacent to each other, the following reaction occurs. When acrylonitrile and acrylic acid or methacrylic acid are placed next to each other, a similar reaction occurs as shown below. When acrylonitrile and acrylamide are bonded next to each other, ammonia is generated in a similar reaction to form a glutaroimide ring.
Heat-resistant heterocycles similar to this may also be created. An example of the change in the infrared absorption spectrum of the polymer according to the present invention due to heat treatment is shown in FIG. This figure shows a spectrum in the range of 2800 to 1500 cm ^-1 , but the absorption at 2240 cm ^-1 due to the stretching vibration of -C≡N decreases, and the absorption at 1690 cm -1 due to the stretching vibration of =C=O
Absorption near cm ^-1 appears. This indicates that the above-mentioned glutaroimide ring is produced. Furthermore, the appearance of absorption near 1620 cm ^-1 seen in this figure is considered to be due to the formation of =C=N group, which suggests the formation of a glutaroimidine ring represented by the following formula. It is clear that this reaction occurs when acrylonitrile molecules are next to each other. The ammonia necessary for this reaction is generated when acrylonitrile and acrylamide are placed next to each other. As described above, in the polymer according to the present invention, the main component, acrylonitrile, may be used by itself or other components, such as acrylic esters, methacrylic esters, acrylamides, and organic compounds having polymerizable unsaturated bonds. It is clear that when acrylonitrile is adjacent to either acid, a heterocycle-forming reaction occurs between the -C≡N group of acrylonitrile and the adjacent functional group upon heating, creating a heat-resistant polymer. It was done. In this invention, the above-mentioned components are copolymerized in order to form the above-mentioned heterocyclic heat-resistant structure, and the blending ratio of these components is determined by the resin obtained.
30 to 80 parts of acrylonitrile, particularly preferably 50 to 80 parts, and 5 to 50 parts of acrylic acid esters, particularly preferably 5 to 30 parts per 100 parts (same parts by weight).
5 to 50 parts of methacrylic acid esters, particularly preferably 5 to 25 parts, 2 to 30 parts of acrylamides, particularly preferably 5 to 20 parts, 2 to 20 parts of organic acids having polymerizable unsaturated bonds, particularly preferably is preferably in the range of 3 to 15 parts. Acrylonitrile is a basic component that forms a heat-resistant heterocyclic structure, and if its amount is less than the above range, the heat softening resistance will decrease, and the chemical resistance, heat resistance, and abrasion resistance will decrease.
If it exceeds this range, the flexibility and crazing resistance of the film will deteriorate, which is not preferable. If the amount of acrylic esters is too low than the above range, the flexibility of the film will decrease, and if it is too high, the heat resistance, heat softening resistance, and abrasion resistance will decrease, and baking or heat treatment at high temperatures will not be possible, resulting in poor heat resistance. This is not preferable because a heterocyclic structure cannot be formed. If the amount of methacrylic acid esters is too less than the above range, the insulation resistance will decrease, and if it is too much, flexibility and chemical resistance will decrease, which is not preferable. If the amount of acrylamide is less than the above range, the crosslinking reaction will not proceed, resulting in lower heat softening resistance and lower abrasion resistance, and if it is too much, flexibility will be decreased, which is not preferable. If the amount of the organic acid having a polymerizable unsaturated bond is less than the above range, the crosslinking reaction will not proceed, resulting in a decrease in heat resistance and heat softening resistance, and if it is too much, the insulation resistance and dielectric breakdown voltage will decrease, which is undesirable. Examples of acrylic esters that can be used in the present invention include methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, n-propyl acrylate,
Examples include isopropyl acrylate, n-pentyl acrylate, and n-hexyl acrylate, and these can be used alone or in combination of two or more. Examples of methacrylic acid esters that can be used in the present invention include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-
Mention may be made of pentyl methacrylate, n-hexyl methacrylate, and mixtures of two or more thereof. Examples of acrylamides that can be used in the present invention include acrylamide, methacrylamide, N-methylol acrylamide, N-ethoxymethyl acrylamide, N-n-propoxymethyl acrylamide, N-n-butoxymethyl acrylamide, N-n- Examples include pentyloxymethylacrylamide, N-propoxyethylacrylamide, Nn-butoxyethylacrylamide, and mixtures of two or more of these. Examples of the organic acid having a polymerizable unsaturated bond that can be used in the present invention include methacrylic acid, acrylic acid, and mixtures of two or more thereof. Therefore, the desired heat-resistant resin can be easily obtained by copolymerizing the resin prepared as described above using a conventional method. That is, in the present invention, the method of copolymerization is not particularly limited, and ordinary solution polymerization, emulsion polymerization, block polymerization, or suspension polymerization can be used as appropriate. A catalyst such as a peroxide is preferably used in the reaction, and a redox catalyst can also be used in combination. The reaction is usually easily carried out by heating at a temperature up to about 100 DEG C. for 4 to 5 hours, or for 1 to 2 hours when a redox catalyst is used. In the case of emulsion polymerization, a surfactant is used, and heating is usually performed at a temperature of about 50 to 80°C. The resin obtained as above is particularly heat resistant,
It has excellent mechanical properties and is useful as various electrical insulating materials, such as wire coatings and impregnated resins. In addition, if the above-mentioned acrylamide is not used in the method of the present invention, the heat softening resistance of the resin will be significantly reduced, and the crosslinking reaction will not proceed, making it impossible to obtain sufficient mechanical strength. Since ammonia is not generated due to the reaction when acrylonitriles are combined, the cyclization reaction when acrylonitriles are adjacent to each other becomes difficult to occur, resulting in a significant decrease in heat resistance. If an organic acid such as methacrylic acid is not used, the heat softening resistance of the resin will be significantly reduced, and the crosslinking reaction will not proceed, resulting in a decrease in mechanical strength and a decrease in glass transition temperature. This invention will be described in detail below with reference to Examples and Comparative Examples. Comparative Example A polymer was obtained by copolymerizing 50 parts of acrylonitrile, 40 parts of styrene, and 10 parts of glycidyl methacrylate in DMF using benzoyl peroxide as a catalyst.
This polymer had poor chemical resistance and poor heat resistance. Example 1 60 parts of acrylonitrile, 20 parts of ethyl acrylate
10 parts of methyl methacrylate, 5 parts of acrylamide, and 5 parts of methacrylic acid were copolymerized in DMF using benzoyl peroxide as a catalyst to obtain a polymer. This polymer had excellent heat resistance, thermal shock resistance, heat softening resistance, and chemical resistance, and also had good flexibility. Examples 2 to 11 Monomers having various composition ratios shown in Table 1 were copolymerized in the same manner as in Example 1 to obtain polymers. All of these polymers have excellent heat resistance, thermal shock resistance, heat softening resistance, and chemical resistance.
Flexibility was also good. The thermogravimetric curves of the polymers obtained in Comparative Example 1 and Example 1, and the change in tensile strength due to heat treatment are shown in the second graph.
, and FIG. 3. From these results, it can be seen that the polymer obtained in Example 1 has significantly better heat resistance, higher crosslink density, and better mechanical properties than the polymer obtained in Comparative Example 1. 【table】

[Brief explanation of the drawing]

Figure 1 is a diagram showing changes in infrared absorption spectra due to heat treatment of the polymer according to the present invention, Figure 2 is a diagram showing thermogravimetric curves of the polymers obtained in Comparative Example 1 and Example 1, and Figure 3 is a diagram showing the tensile strength curves of the polymers obtained in Comparative Example 1 and Example 1. FIG. 3 is a diagram showing changes in the thickness due to heat treatment.

Claims (1)

[Claims] 1. 30 to 80 parts by weight of acrylonitrile and 5 to 80 parts by weight of acrylic esters per 100 parts by weight of the resulting resin.
Heat resistance characterized by copolymerizing 50 parts by weight, 5 to 50 parts by weight of methacrylic acid esters, 2 to 30 parts by weight of acrylamide, and 2 to 20 parts by weight of methacrylic acid or acrylic acid having a polymerizable unsaturated bond. Method of manufacturing resin. 2 As acrylic esters, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, n-propyl acrylate, isopropyl acrylate, n-
The method for producing a heat-resistant resin according to claim 1, characterized in that at least one compound selected from the group consisting of pentyl acrylate and n-hexyl acrylate is used. 3. At least one compound selected from the group consisting of methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-pentyl methacrylate, and n-hexyl methacrylate as the methacrylic ester. A method for producing a heat-resistant resin according to claim 1 or 2, characterized in that the method is used. 4 As acrylamides, acrylamide,
Methacrylamide, N-methylolacrylamide, N-ethoxymethylacrylamide, N-n
-Using at least one compound selected from the group consisting of propoxymethylacrylamide, Nn-butoxymethylacrylamide, Nn-pentyloxymethylacrylamide, N-propoxyethylacrylamide, and Nn-butoxyethylacrylamide. A method for producing a heat-resistant resin according to any one of claims 1 to 3, characterized in that: