KR20010001967A - A composition of modified polyamide resin - Google Patents

Abstract

PURPOSE: The subject resin composition prepared by adding polyacetal homopolymer or polyacetal copolymer to polyamide resin in place of forming a polymer by polymerization of caprolactam or hexamethylenediamine as a monomer and formamide in a process of polyamide polymerizations is provided, which can simplify the producing process of modified polyamide resin and produce a small amount according to each article or various kinds of products. CONSTITUTION: The resin composition is obtained by melt mixing 0.5 to 25 parts by weight of polyacetal resin with 100 parts by weight of polyamide resin as a main component. The polyamide resin is obtained by polymerization of one or two or more selected from caprolactam, hexamethylenediamine, adipic acid and diaminophthalic acid. The polymide resin polymerized with caprolactam has an isothermal maximum crystallization velocity of 1.3 to 3.5 min at 200 deg.C. and polyamide resin polymerized with hexamethylenediamine-adipig acid 1.5 to 4.0 at 230 deg.C

Description

Modified polyamide resin composition

The present invention relates to a modified polyamide resin composition, and more particularly, the polyamide resin contains a polyacetal homopolymer represented by the following Chemical Formula 1 or a polyacetalated copolymer represented by the following Chemical Formula 2 to prevent decomposition of polyacetal. By inducing the reaction between the formaldehyde formed by induction and the polyamide resin to form an alkoxymethyl group in the molecular chain of the polyamide resin, it is possible to simplify the manufacturing process of the modified polyamide, and to produce a small amount or a multi-product for each product. The present invention relates to a modified polyamide resin composition, which can be enabled and also controls the rapid crystallization rate shown in conventional polyamide resins, thereby easily controlling the molded article surface state of the resin or filler-reinforced resin and controlling physical properties.

Formula 1

In Formula 1, n is an integer of 1 to 100,000.

Formula 2

In Formula 2, R is an alkyl group having 1 to 3 carbon atoms or an aryl group, and m is an integer of 1 to 10,000.

Polyamide is showing a trend of replacing materials such as thermosetting resins with nylon, with the recycling of materials, the development of related industries such as the electric, electronics, and automobile industries worldwide and an average annual growth of more than 10%. In addition, more than 30% of the nylon resin as an engineering plastic is used as a compounding resin containing a filler and various additives. These polyamide resins have been commercialized through processing such as injection and extrusion. Because polyamide resins have excellent mechanical properties such as strength, rigidity and abrasion resistance, and have good heat resistance, dimensional stability, and moldability, automotive parts and electrical / electronic parts It is widely used in various industrial fields. However, molding defects frequently occur due to high molding conditions and high water absorption. In particular, when a large amount of fillers and additives are contained, surface defects and physical property changes may occur largely due to the rapid crystallization temperature and crystallization rate.

In order to solve the problem of the crystalline polyamide can be controlled through the modification of the polyamide resin, the method of modifying the polyamide so far is as follows.

The most common method of modifying polyamide is mainly to form a copolymer or to modify the polyamide homopolymer by adding a plasticizer, a release agent, or a polyolefin resin substituted with maleic anhydride as a third polymer. do. In addition, there is also known a method of binding and forming an alkoxymethyl group by reacting an amide group with a polyamide resin, such as formaldehyde.In polymerization, alkoxymethyl group is substituted with lactam or hexamethylenediamine, which is a monomer of the polyamide resin, to crystallize Crystallinity, melting point and the like can be controlled [Biggs, BD, Ind. Eng. Chem., 38, 1016 (1946); Cairns, J. L., Am. Chem. Soc., 71, 651 (1946).

In addition, the polyamide resin as a polymer is reactive with formaldehyde. In the production of the polyacetal resin, polyamide resin is used as a capture agent for formaldehyde, and this technique is applied to end group stabilization, thermal stability, and recycling of polyacetal. It imparts the properties, color stability and the like. For example, Japanese Patent Laid-Open Nos. Hei 6-29306 and Hei 6-43544 use 0.1% polyamide to stabilize terminal groups, and in Japanese Patent Laid-Open No. Hei 1-275652, 0.2% gives color stability and thermal stability. In Japanese Patent Application Laid-Open Nos. 3-14860, 7-57838, and 7-91438, four-component copolymers of polyamide 6/66/610/12 are used for excellent recyclability and all molds. The deposit property was given. Japanese Patent Laid-Open No. 5-125255 discloses a polyacetal resin composition having excellent thermal stability and low formaldehyde odor using a polyamide ternary copolymer, and in addition to using a polyamide resin as a modifier of polyacetal. The method is disclosed in Japanese Patent Laid-Open Nos. Hei 6-345937, Hei 6-345938, Hei 7-179725, Hei 7-309994, Hei 6-68059, Hei 7-91440 and the like.

Meanwhile, Korean Patent Publication No. 84-6361 discloses an electrically conductive polyacetal resin composition having thermal stability by containing carbon graphite and 0.1 to 15% by weight of an amide compound in a resin, and Korean Patent Publication No. 88-6317 No. discloses a method of imparting thermal stability of polyacetal by adding in an amount of 0.05 to 2% by weight, and Korean Patent Publication No. 90-9845 discloses melamine, guanidine, urea, guanamine or substituted guanamine and form. Disclosed is a method for producing polyacetal using a prepolymer resin produced by condensation of aldehyde, and Korean Patent Publication No. 92-702702 discloses a method for preparing stabilized polyacetal using a compound containing an amide group. In Korea Patent Publication No. 97-700208, polyacetal component, epoxy group, carboxyl group, acid anhydride group Method for producing modified polyacetal wherein residues of compound having at least one modified group polymerizable unsaturated bond selected from the group consisting of ester group, amino group, amide group and heterocyclic group having nitrogen atom as hetero atom are introduced by addition reaction Korean Patent Laid-Open Publication No. 98-2150 discloses a corrosion protection effect and magnetic tape on metals using specified nitrogen-containing compounds such as melamine and its derivatives, melamine-formaldehyde resins, polyamides and polyacrylamides. Polyacetal resin compositions having reduced adverse effects with respect to and the like are disclosed.

As indicated in the above description, polyamides are added to polyacetals to act primarily as formaldehyde trapping agents, thereby resulting in low thermal stability and color caused by formaldehyde gases during polymerization or processing, which is a problem of conventional polyacetals. It is mainly used to improve stability. In this case the polyamide serves only as an additive of the polyacetal, which is reactive with formaldehyde, in which a modified polyacetal is formed.

However, in the above-described methods, when polyolefin-based resins in which maleic anhydride is substituted are added to polyamides, polyolefin resins have extremely low heat resistance and physical properties compared to polyamides. Loss of physical properties, tensile strength, impact strength, modulus such as modulus and stiffness are lowered, and addition of alkoxyalkyl groups to the monomer of the polyamide resin to modify the method requires an additional one step reaction in the polymerization process. There are many difficulties in terms of time and cost, and there is a problem in that it is not suitable for the optimum high quality, small quantity, and multi-market structure of each component that is currently required at home and abroad.

Accordingly, in the present invention, in order to improve the problems of the prior art in the modification of the polyamide resin as described above, instead of forming a polymer by reacting formaldehyde with caprolactam or hexamethylenediamine as a monomer in polyamide polymerization, a polymer is formed. Although the substitution rate of is slightly decreased, polyamide resin is formed by incorporating polyacetal homopolymer or polyacetalization copolymer into polyamide resin to induce reaction of formaldehyde and polyamide resin formed by inducing decomposition of polyacetal by melt kneading. By forming an alkoxymethyl group in the molecular chain of the polyamide, the process of producing the modified polyamide can be simplified, and it is possible to produce a small amount or multiple kinds of products suitable for each product, and also by controlling the fast crystallization rate shown in the conventional polyamide resin Resin or filler To provide a shaped article of a localized resin surface condition, a modified polyamide resin composition which is easy to adjust the physical properties it is an object.

The present invention for achieving the above object is a polyacetal homopolymer represented by the following formula (1) or a polyacetalized copolymer represented by the following formula (2) with a polyamide resin as a main component, 100 parts by weight of the polyamide resin It is characterized by the modified polyamide resin composition containing 25 weight part.

Formula 1

In Formula 1, n is an integer of 1 to 100,000.

Formula 2

In Formula 2, R is an alkyl group having 1 to 3 carbon atoms or an aryl group, and m is an integer of 1 to 10,000.

The present invention will be described in more detail as follows.

Examples of the polyamide resin used as the main component of the modified polyamide resin according to the present invention include polyamide 66, polyamide 6, polyamide 46, copolymers thereof, and the like. Since the polyamide resin has a high crystallization temperature and crystallization rate, the polyamide resin is also included in the present invention to control the polyamide resin.

As described above, in the present invention, the polyamide resin is contained together with the polyacetal compound to modify the polyamide resin by a reaction as shown in the following Scheme 1.

That is, by incorporating polyacetal homopolymer or polyacetalization copolymer into polyamide resin, the reaction of formaldehyde and polyamide resin formed by inducing decomposition of polyacetal is induced to alkoxymethyl group in the molecular chain of polyamide resin. It will be able to form a modified polyamide by forming.

In said Scheme 1, R is a C1-C3 alkyl group or an aryl group, L is 50-1,000, n is an integer of 1-100,000, m is an integer of 1-10,000.

The polyacetal compound is to react with the nitrogen atom of the polyamide by inducing decomposition of formaldehyde in the molten state as shown in Scheme 1, the polyacetal homopolymer represented by the formula (1) and represented by the formula (2) Among the polyacetalated copolymers, for example, polymethylene oxide, ethylene oxide copolymer, polymethylene oxide-propylene oxide copolymer, polymethylene oxide-dioxolane copolymer and the like are used. As the polyacetal homopolymer or copolymer represented by Chemical Formula 1 or 2, a weight average molecular weight of 5,000 to 150,000 may be used.

Such a polyacetal compound is contained in 0.5-25 weight part with respect to 100 weight part of polyamide resins. If the content is less than 0.5 parts by weight, the effect of improving the crystallization behavior of the polyamide is insufficient when it is added. If the content is more than 25 parts by weight, the smell of unreacted formaldehyde is severely generated during processing such as melt kneading, injection and extrusion. Due to the formaldehyde gas, the working environment worsens, and due to the phase separation of undecomposed acetal and polyamide, severe die casting causes a problem in that the physical properties of the molded article are drastically reduced.

In addition to the polyacetal compound, a heat-resistant body, a reinforcing filler, a releasing agent, a weathering agent, a plasticizer, a flame retardant, a pigment, and the like may be added to the modified polyamide resin of the present invention.

The heat resistant agent is added to prevent thermal decomposition during the polyamide molding process. As the heat resistant agent, heat resistant agents such as copper, phenol, and aromatic amines are used. Add 2.0 parts by weight. If the amount of the heat resistant agent is less than 0.1 part by weight, the effect of improving heat resistance is insignificant, and if it exceeds 2.0 parts by weight, there is a problem in that the mechanical properties of the final product are lowered.

In addition, since the reinforcing filler is added to impart mechanical strength and rigidity, the surface of the reinforcing filler is preferably surface-treated with a urethane-based polymer and amino silane to maintain interfacial adhesion with polyamide. Such reinforcing fillers include talc and clay. Mineral or glass fibers such as ulastonite, etc., are used in an amount of 100 parts by weight or less based on 100 parts by weight of polyamide. In addition, in the case of glass fiber, the length and diameter of the glass fiber can be appropriately changed according to the required properties. If the content of the reinforcing filler exceeds 100 parts by weight, there is a problem that the improvement of the surface of the molded article due to the modification of the polyamide has a slight improvement effect due to the severe expression of glass fibers or minerals.

The modified polyamide resin of the present invention as described above melt-kneaded the polyacetal resin to the polyamide resin to induce the formation of the alkoxymethyl group in the polyamide resin, so that the modified polyamide resin mainly containing polyamide 66 is 230 ° C. The modified isotropic polyamide resin having an isothermal maximum crystallization rate of 1.5 to 4.0 minutes and polyamide 6 as the main component has an isothermal maximum crystallization rate of 1.3 to 3.5 minutes at 200 ° C., resulting in crystallization behavior such as crystallization temperature, crystallization rate and melting point of the polyamide. By controlling the molding, the surface of the molded article is beautiful and the overall physical properties of the molded article can be properly adjusted.

Although this invention is demonstrated in detail based on an Example, this invention is not limited to an Example.

Example 1

Next, after mixing 0.5 parts by weight of polyacetal resin (K-300, K-300) and 0.2 parts by weight of heat-resistant agent (IRGANOX-1010, Switzerland) to polyamide 6 as shown in Table 1, 250 to 290 ° C After melt mixing using a continuous screw-type twin screw extruder heated in the form of a modified polyamide into pellets, and dried in a dehumidifying dryer at 90 ℃ for 6 hours to remove moisture, Perkin-Elmer (Perkin- Elmer) The thermal and crystallization characteristics were measured by DSC7, and the results are shown in Table 2 below. After the test pieces were prepared by using an injection molding machine, pelletized resins were observed on the surface and molding.

Examples 2-5

It was carried out in the same composition as shown in Table 1 and was carried out in the same manner as in Example 1 except that the glass fiber was added to the feedstock inlet of the extruder.

Examples 6-10

The same composition as in Examples 1 to 5, except that polyamide 6 was changed to polyamide 66.

Examples 11-12

Except for changing the glass fiber content of Example 8 was carried out in the same manner as in Example 8.

Comparative Examples 1 to 9

The composition shown in Table 1 was the same method as in Example 1.

division Polyamide (parts by weight) Polyacetal ³⁾ (parts by weight) Heat Resistant ⁴⁾ (parts by weight) Glass fiber ⁵⁾ (by weight) N-6 ¹⁾ N-66 ²⁾ Example 1 100 - 0.5 0.2 - Example 2 100 - 2 0.2 - Example 3 100 - 5 0.2 - Example 4 100 - 10 0.2 - Example 5 100 - 20 0.2 - Example 6 - 100 0.5 0.2 - Example 7 - 100 2 0.2 - Example 8 - 100 5 0.2 - Example 9 - 100 10 0.2 - Example 10 - 100 20 0.2 - Example 11 - 100 5 0.2 50 Example 12 - 100 5 0.2 100 Comparative Example 1 100 - - 0.2 - Comparative Example 2 100 - 0.3 0.2 - Comparative Example 3 100 - 30 0.2 - Comparative Example 4 - 100 - 0.2 - Comparative Example 5 - 100 0.3 0.2 - Comparative Example 6 - 100 30 0.2 - Comparative Example 7 - 100 - 0.2 50 Comparative Example 8 - 100 - 0.2 100 Comparative Example 9 - 100 5 0.2 120 1) Polyamide having a relative viscosity of 2.6 by sulfuric acid method 6 2) Polyamide having a relative viscosity of 2.5 by sulfuric acid method 3 3) KTP KOCETAL of grade 9 with melt flow index, grade-K300 4) , IRGANOX-1010 5) Surface-treated with acrylic polymer and aminosilane

division Glass transition temperature ¹⁾ (℃) Crystallization temperature ²⁾ (℃) Isothermal maximum crystallization rate ³⁾ (min) Example 1 44.0 170 1.50 Example 2 42.1 165 1.56 Example 3 38.2 156 2.12 Example 4 33.1 152 2.85 Example 5 31.7 150 3.36 Example 6 43.1 224 1.30 Example 7 41.4 219 1.37 Example 8 37.7 211 1.53 Example 9 32.5 206 2.34 Example 10 30.8 203 3.03 Example 11 39.6 216 1.42 Example 12 39.8 217 1.40 Comparative Example 1 44.4 172 1.43 Comparative Example 2 44.3 171 1.43 Comparative Example 3 30.1 148 3.49 Comparative Example 4 43.4 226 1.22 Comparative Example 5 43.4 225 1.22 Comparative Example 6 29.7 201 3.27 Comparative Example 7 48.2 228 0.96 Comparative Example 8 48.2 228 0.95 Comparative Example 9 48.6 227 0.11 Note 1) Glass transition temperature stays at 280 ° C for 7 minutes, and then it is quenched after thermal homogenization and measured at a temperature increase rate of 20 ° C / min. 2) Crystallization temperature starts at 280 after staying at 280 ° C for 3 minutes. 3) Polyamide 6 was measured at 200 ° C., and polyamide 66 was measured at 230 ° C.

As shown in Table 2, the modified polyamide resin prepared in the above-mentioned Example not only has excellent workability, surface and the like but also has a low gloss surface. On the contrary, in the comparative example, the smell of formaldehyde is severe, the mixing is poor, dieswelling occurs, crystallization rate is very fast, and the surface state is also poor. In addition, the modified polyamide resin according to the present invention is an isothermal maximum crystallization at 230 ℃ when the polyacetalization resin is kneaded during melt kneading to solve the difficulties in the processing process, which was pointed out as a conventional problem, the polyamide 66 as a main component The speed is 1.5 to 4.0 minutes, and in the case of polyamide 6, it can be seen that the melt crystallization behavior of the original polyamide resin can be effectively controlled as the isothermal maximum crystallization rate is 1.3 to 3.5 minutes at 200 ° C.

The modified polyamide resin of the present invention has solved the problems of the conventional polyamide 6 or polyamide 66 through the simple and effective control technique as described above, namely, the fast crystallization rate, the surface defect of the reinforced resin, etc. It is believed that more complicated molded parts can produce superior effects.

As described above, the modified polyamide resin according to the present invention induces a reaction of formaldehyde and polyamide resin formed by inducing decomposition of polyacetal to form an alkoxymethyl group in the molecular chain of the polyamide resin, thereby modifying the polyamide. It is possible to simplify the manufacturing process of the product, to enable the production of small quantities or multiple varieties suitable for each product, and also to control the fast crystallization rate shown in the conventional polyamide resin, and to improve the molded article surface state of the resin or filler-reinforced resin, Easy to control physical properties

Claims (4)

The modified polyamide resin composition which melt-kneaded 0.5-25 weight part of polyacetal resins with respect to 100 weight part of polyamide resins as a polyamide resin as a main component. The modified polyamide resin composition according to claim 1, wherein the polyamide resin is polymerized with one or two or more selected from caprolactam, hexamethylenediamine, adipic acid and diaminophthalic acid. The modified polyamide resin composition according to claim 2, wherein the polyamide resin polymerized with caprolactam has an isothermal maximum crystallization rate of 1.3 to 3.5 minutes at 200 ° C. 3. The modified polyamide resin composition according to claim 2, wherein the polyamide resin polymerized with hexamethylenediamine-adipic acid has an isothermal maximum crystallization rate of 1.5 to 4.0 minutes at 230 deg.