KR100224058B1 - Polyamide resin composition made from recycled plastics - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyamide resin composition using recycled products. More specifically, the present invention relates to automobiles by containing polyamide recycled resin and waste polyvinyl butyral (PVB) as a main component and containing thermoplastic fibers and glass fibers as reinforcing fibers. Polyamide that can be used as a polymer molding material in the production of automobile parts such as connectors and accelerators, or regenerated parts such as pipes and helmets, while conserving resources, saving energy, and protecting the environment through recycling of parts. It relates to a resin composition.

Description

Polyamide Resin Composition Using Recycled Products

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyamide resin composition using recycled products. More specifically, the present invention relates to automobiles by containing polyamide recycled resin and waste polyvinyl butyral (PVB) as a main component and containing thermoplastic fibers and glass fibers as reinforcing fibers. Polyamide that can be used as a polymer molding material in the production of automobile parts such as connectors and accelerators, or regenerated parts such as pipes and helmets, while conserving resources, saving energy, and protecting the environment through recycling of parts. It relates to a resin composition.

In general, polyamide is an engineering plastic, which has high strength, elasticity, and high solvent resistance. Therefore, polyamide is widely used in automotive parts such as resistors, connectors, and accelerators, as well as automotive interior materials or industrial machinery such as various valves, connector housings, pipes, and helmets. It is used for a purpose. However, these polyamide resins have a disadvantage in that impact resistance is poor and dimensional stability is lowered due to being sensitive to moisture.

Therefore, in order to make up for the shortcomings of the conventional polyamide, polymers having excellent impact resistance or rubber properties at room temperature are plasticized at high temperature, but easily molded and blended with thermoplastic elastomers having high strength, which are sensitive to impact resistance and moisture absorption. Research has been conducted to improve the quality of the product. However, the impact reinforcing polymer having high impact resistance, which is miscible with polyamide, and the production cost of the thermoplastic elastomer is expensive or mostly imported compared to general-purpose resins, so it is not efficient considering economical aspects. In addition, research has been conducted to improve mechanical properties such as impact resistance and tensile strength by filling 30 to 50% of polyamide with glass or carbon fibers, which are reinforcing fibers. However, reinforcing fibers are relatively expensive and the interface between the matrix and the reinforcing fibers Due to the weak bonding strength, the improvement of mechanical properties including impact resistance was poor. Despite the disadvantages of poor impact resistance and sensitivity to moisture absorption, polyamide resins, which are engineering plastics, have excellent heat resistance and mechanical strength, compared to other resins, and thus are increasingly used in various applications. As the development of various industries and the national income increased, the use of various plastics increased rapidly, and their waste also increased exponentially in proportion to environmental pollution as well as to deal with it. In 1990, the proportion of rubber and plastics belonging to polymers in urban wastes reached 11.4%, which was discarded by landfilling and incineration. Recycling of plastics is also important for recycling itself, but in order to protect the environment, the focus should be on minimizing secondary environmental pollution. In terms of recycling itself, recycled plastics form materials that are manufactured at high cost and effort. Recycling is the best way to use materials directly, without the need for incineration, landfilling or re-decomposition. Currently, the recycling of waste plastics in Korea is limited to general-purpose plastics such as polyethylene (PE), polystyrene (PS), and polypropylene (PP), and recycling of engineering plastics such as polyamide and polycarbonate, which are relatively expensive. Is insignificant.

On the other hand, polyvinyl butyral (hereinafter referred to as PVB) is imported at a high price, and the total amount of molding resin is about 5%, and 95% of the film type PVB has excellent adhesiveness and transparency between glass and glass. It is used as a safety glass laminate film for automobiles and aircrafts because it is useful for preventing safety accidents because glass fragments are attached to the film surface instead of flying when the windshield breaks.

PVB is a copolymer of polyvinyl alcohol, polyvinyl acetal and polyvinylacetate, and is synthesized by reacting polyvinyl alcohol, which is a hydrolysis product of polyvinylacetate, with n-butylaldehyde to acetalize it. Therefore, in addition to the acetal group, a hydroxyl group exists in the molecular structure. The hydroxyl group is present in a relatively large amount of 11 to 25% because it reacts with the silane group present in the glass in automobile safety glass to promote the adhesion between the glass and PVB.

In addition, PVB is mainly used products of Monsanto (trade name: Butvar) and Dupont (trade name: Butacite) having a molecular weight of about 55,000 to 200,000.

Waste PVB is a scrap from the glass-cutting process when making safety glass in automotive safety glass production plants, accounting for about 20% of the total requirement, all of which are being discarded. Unlike other general-purpose resins, PVB film is expensive and has strong adhesive force, so that the film adheres to each other at the time of reclamation and turns into a large waste, and it takes longer and takes longer to decompose than other wastes, especially when maximizing resource regeneration effect and considering environmental conservation. Resin that requires recycling. Since other additives are added to the PVB film in addition to the plasticizer, when the plasticizer and other additives are removed in the recycling process and recycled for the PVB film, the physical properties are lower than the original adhesive strength. There is a problem that follows.

In the present invention, while exploring the effective use of the polyamide and waste PVB, in order to recycle the polyamide resin, which is an engineering plastic, and to improve impact resistance and dimensional stability, which is a representative disadvantage of polyamide, Waste polyvinyl butyral, a scrap from the automobile safety glass production process, is used as a reinforcing agent for polymers with low impact resistance as impact reinforcing agent, solving resource conservation and environmental pollution problems, and adding appropriate amount of reinforcing fiber to diversify the application. It is to provide a polyamide resin with further improved mechanical properties such as impact resistance, tensile strength.

1 is a scanning electron micrograph (2,000 times) of a two-component blend composed of polyamide recycled resin and waste polyvinyl butyral of the present invention.

FIG. 2 is a scanning electron microscope for a three-component blend containing the polyamide recycled resin, waste polyvinyl butyral and SEBS-g-MA (maleic anhydride graft modified product of styrene-ethylene-butylene-styrene) of the present invention. It is photograph (2,000 times).

The present invention is a polyamide resin composition containing a polyamide resin and a polyvinyl butyral component,

(A) 30 to 90% by weight of polyamide recycled resin,

(B) 20 wt% or less of polyamide raw material having an inherent viscosity of 0.5 to 2.5 dl / g,

(C) 10 to 40% by weight of waste polyvinylbutyral component containing 10 to 35% of hydroxyl groups, or

(D) at least one selected from the maleated thermoplastic elastomer or reinforcing fibers, characterized in that it contains 10% by weight or less.

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

The present invention relates to a polyamide resin prepared by using (a) a polyamide recycled material, (b) a polyamide virgin material, and (c) a waste polyvinyl butyral component consisting of waste resources. In order to reinforce the impact resistance, (d) a block copolymer represented by S1-EB-S2 (where S1 and S2 represent polystyrene blocks and EB represents an ethylene / butylene copolymer block) and ethylene / propylene rubber Maleic anhydride graft modified materials (hereinafter referred to as SEBS-g-MA and EPM-g-MA, respectively) or glass fibers or the like may be mixed and used. Such use components of the present invention are polyamide resin compositions that can be used to mold the melt-kneaded material into automobile parts such as connectors, accelerators, or the like, and various shapes such as valves, pipes, and helmets.

Polyamides usable in the present invention are polypyrrolidone (nylon 4), polycaprolactam (nylon 6), polyhexamethylene adipamide (nylon 6,6), polyheptolactam (nylon 7), polynonanolactam (nylon) 9) or conventionally known polyamide raw materials such as polydodecanolactam (nylon 12) and recycled resins. In this case, the polyamide raw materials used are those having an intrinsic viscosity of 0.5 to 2.5 dl / g. If the intrinsic viscosity exceeds 2.5, the stiffness and chemical resistance are excellent, but molding is difficult, and molding is less than 0.5. Although the processing is excellent, there is a problem that the rigidity, the stress resistance is reduced.

In addition, the waste polyvinyl butyral (PVB) film used in the present invention has a Staudinger molecular weight of 50,000 to 600,000, preferably 55,000 to 200,000, and is calculated as polyvinyl alcohol based on the total weight. 10-35% of hydroxyl groups, 5% or less of ester groups as calculated as polyvinyl esters, 2.5% or less of acetate groups as calculated as polyvinyl esters, and the rest consisting of butyral groups are used. These waste PVBs are prepared by the reaction of polyvinyl alcohol with butylaldehyde in the presence of an acid catalyst to produce PVB, followed by neutralization by a catalyst, and aqueous or solvent acetylation reactions through separation, stabilization and drying of the PVB resin. .

In addition, glass fiber as a reinforcing fiber has an e-glass (E) having a high density of 2.0 to 2.8 g / cm 3, a fiber of 10 to 15 μm, a tensile strength of 2500 to 3500 MPa, and a high modulus of 60 to 80 GPa. -glass, manufactured by Faiba Korea) is used.

In the SEBS-g-MA which is a compatibilizer, the content of the ethylene / butylene (EB) block copolymer constituting these blocks is 30 to 90% by weight, preferably 50 to 80% by weight in the SEBS copolymer. The weight ratio S1 / S2 of the styrene blocks S1 and S2 is 10 to 70% by weight, more preferably 20 to 50% by weight. The number average molecular weight of the SEBS-g-MA copolymer is preferably 5,000 to 50,000, more preferably 10,000 to 30,000. If the molecular weight is large, it does not act as a compatibility enhancer to improve the interfacial adhesion between the two phases, if too small, there is a problem such as not acting as a surfactant, so the molecular weight is effective to the maximum limit.

This copolymer is a graft polymerized maleic anhydride to the SEBS copolymer, and maleic anhydride is graft copolymerized to a part of the EB block of the SEBS copolymer. The maleic anhydride content grafted to the SEBS-g-MA copolymer is 0.5 to 10 wt% with respect to the SEBS copolymer, preferably 1 to 5 wt%. If the grafted maleic anhydride content is too small, the grafting reaction of the polyamide with the terminal amine group is difficult to occur, and if too large, the interfacial adhesion force is lowered due to the excessive reaction. The EPM-g-MA copolymer has a number average molecular weight of 10,000 to 50,000, preferably 35,000 to 40,000, and the maleic anhydride content grafted to the copolymer is 0.5 to 10% by weight, preferably 1 to 1, based on the EPM copolymer. 5 weight percent is good.

The molding material of the present invention can be obtained by kneading extrusion of a polyamide recycled resin, a polyamide raw material, a waste PVB film, a compatibilizer or a glass fiber. When the mixing ratio of polyamide recycled resin, polyamide raw material, waste PVB film, compatibilizer or glass fiber is shown, polyamide recycled resin is 30 to 90% by weight, more preferably 60 to 80% by weight of the total composition. %, The unused polyamide raw material is 20% by weight or less based on the total weight of the composition, and the waste PVB is 10-40% by weight, more preferably 20-40% by weight, based on the weight of the total composition. In addition, the glass fiber as the reinforcing fiber is preferably 10% by weight or less with respect to the total weight of the composition. If the content exceeds 10% by weight, the elastic modulus and the flexural strength are improved, but the interfacial adhesion with the matrix decreases and the elongation is small. There is a problem.

In addition, the content of the compatibilizer containing a polar group is preferably 10% by weight or less based on the total composition content, more preferably 2 to 10% by weight. If the content is more than 10% by weight, there is a problem in that the amine group of nylon as an matrix and the anhydride of the compatibilizer are overreacted, thereby deteriorating physical properties.

In this case, the melting and kneading temperature of the molding material is preferably at least the temperature at which the polyamide component is melted. In said melt blend, usual additives, such as a filler, a coloring agent, a flame retardant, antioxidant, can be added. The molding material of the present invention is usually handled in pellet form.

The molding material of the present invention has excellent impact resistance and elongation characteristics by polyamide recycled resin, waste PVB and thermoplastic elastomers containing polar groups such as SEBS-g-MA and EPM-g-MA. This is a phenomenon that the interfacial tension decreases because the maleated thermoplastic elastomer is present between the polyamide and PVB interfaces, and the amine group (-NH2) at the end of the polyamide reacts with the anhydride of the thermoplastic elastomer to form graft copolymerization. This is because the adhesion is improved, and this relationship is shown in Scheme 1 below.

Also, by adding the glass fiber reinforcement to the polyamide recycled resin / waste PVB blend, a polymer material having improved tensile strength and impact resistance can be prepared than the blend of the polyamide recycled resin / waste PVB / compatibilizer to have a poly An amide resin composition can be obtained. Antioxidants are added to prevent the formation or oxidation of low molecular weight polymers that occur when extrusion of polyamide recycled resin, waste PVB and compatibilizers or glass fibers. The antioxidant used may be 2'-6-di-tert-butyl-4'-methylphenol (2'-6-di-tert-butyl-4'-methylphenol, BHT).

According to the present invention, the molding material can be produced by extrusion molding and injection molding into various shaped articles. In the case of extrusion molding, each component such as polyamide recycled resin, waste PVB and SEBS-g-MA, EPM-g-MA, or glass fiber reinforcement is adjusted to an appropriate amount and fed into a molding machine, and melt-kneaded therein. It is possible to produce by extrusion molding from a die at the tip of the molding machine.

Next, the present invention will be described based on Examples. However, the present invention is not limited to the Examples.

EXAMPLES 1-4

Polyamide Resin / Waste PVB Blend

Polyamide recycled resin was used after crushing waste scrap and defective products generated during the production process of the headlamp housing, which is an automobile part, and then pulverizing it to a diameter of about 5 to 6 mm. The impact strength of the polyamide recycled resin was 7.86 KJ / ㎡, which was somewhat lower than that of the raw materials, because the aging after molding or the inclusion of foreign matters during the crushing and grinding process. Since waste PVB films tend to adhere to each other at room temperature and are difficult to grind to a constant size, the waste PVB films were pelletized by grinding to a constant size of about 3 mm using a grinder at a low temperature. The components used and their contents are shown in Table 1a.

The polyamide recycled resin and waste PVB film described above were put in a vacuum oven and heated and dried at 80 ° C. for at least 12 hours to remove moisture adsorbed on the surface, followed by extrusion kneading.

Extrusion kneading of polyamide recycled resin and waste PVB film was carried out using a model PL2000 twin screw extruder (screw diameter 42 mm, L / D 7, counter rotating) manufactured by Brabender Co., Ltd. The extrusion kneading was carried out by mixing the screw rotation speed at 60 rpm at / 260 ℃.

[Examples 5 to 13]

Polyamide Recycled Resin / Waste PVB / SEBS-g-MA / EPM-g-MA Blend

Polyamide recycled resin and waste PVB were used in the same manner as in Examples 1 to 4.

SEBS-g-MA (styrene-ethylene-butylene-styrene) used as a compatibilizer, which is a thermoplastic elastomer, was made of Kraton 1901 (Kraton 1901, manufactured by Shell Company), which graft copolymerized maleic anhydride to a ternary block copolymer. The number average molecular weight of this compound is 20,000, styrene content is 29 weight% and maleic anhydride content is 2 weight% with respect to SEBS.

EPM-g-MA (copolymer) used as another compatibilizer used a number average molecular weight of 40,000 to 50,000 and a maleic anhydride content of 1.2% by weight relative to ethylene / propylene rubber (EPM). Extrusion kneading process was carried out in the same manner as in Examples 1 to 4 and the components and their contents are shown in Table 1a.

[Examples 14-20]

Polyamide Resin Resin / Polyamide Raw Material / Pe PVB / SEBS-g-MA

Blend

Polyamide recycled resin and waste PVB were the same as those used in Examples 1 to 4 above, and nylon 6 (topramide 1033T, Tong Yang Nylon Co., Ltd.) was used as the polyamide raw material, and the impact strength of the polyamide raw material was about 8.1 KJ / A high viscosity resin having a melting point of 220 m < 2 > was used.

SEBS-g-MA was used as a compatibilizer, and the extrusion kneading process was carried out in the same manner as in the above example, and its components and contents are shown in Table 1a.

[Examples 21 to 25]

Polyamide Recycled Resin / Polyamide Raw Material / Waste PVB / Glass Fiber

Blend

Polyamide recycled resin, polyamide raw material and waste PVB were used in the same manner as in the above examples.

Reinforcing glass fibers (Glass Fiber, manufactured by Fiber Korea) used an E-type with a density of 2.54, a tensile strength of 3448 MPa, and an elastic modulus of 72.4 GPa. In general, when reinforcing fibers are added to polyamide, the surface of the fibers is treated with silane or the like to enhance the interfacial bonding force between the matrix and the reinforcing fibers. A polysulfide-based Ucarsil RC-2 silane coupling agent (Union Carbide Co., Ltd.) was selected and diluted in a cosolvent (butt ratio 95: 5) of butanol and distilled water, followed by pH using acetic acid. Was adjusted to 3.5, the concentration was 0.3% by weight, and then hydrolyzed for 1 hour. The glass fiber was impregnated with the hydrolyzed solution for 10 minutes, then taken out, dried at room temperature for 48 hours, and then surface treated, and dried at 200 ° C. for at least 16 hours prior to extrusion kneading to remove moisture adsorbed onto the glass fiber surface. . Extrusion kneading process was carried out in the same manner as in the above Example and the components and contents used are shown in Table 1a.

[Comparative Examples 1 to 4]

Polyamide Raw Materials / PVB Blends (Examples 1 to 2, 4 and 9 of Korean Patent Application No. 96-8029)

Nylon 6 (topramide 1033T, product of Tong Yang Nylon) was used as the polyamide raw material, and polyvinyl butyral resin had a specific gravity of 1.07 to 1.08 and a resin of DuPont (trade name: Butacite) containing 28 to 30% of a plasticizer. Used. Extrusion kneading process was carried out in the same manner as in the above Example and its components and contents are shown in Table 1b.

[Comparative Examples 5-8]

Blend of Polyamide Raw Material / SEBS Block Copolymer

Nylon 6 (topramide 1033T, manufactured by Dongyang Nylon) was used as the polyamide. SEBS (trade name: Kraton 1652, manufactured by Shell Co., Ltd.) in which styrene was copolymerized at the sock end of an ethylene / butylene (EB) copolymer, which is a conventional impact modifier, was used. SEBS has a styrene block number average molecular weight of 7,000, an EB block number average molecular weight of 37,500, and its styrene content is 29% by weight. Extrusion kneading process was carried out in the same manner as in the above examples and their components and contents are shown in Table 1b.

TABLE 1a

TABLE 1b

Experimental Example 1

The samples granulated by extrusion kneading in Examples 1 to 25 and Comparative Examples 1 to 8 were dried in a vacuum oven at 80 ° C. to remove moisture, and then the specimens were prepared under the conditions shown in Table 2.

Tensile strength and modulus of elasticity of the prepared materials were measured using a universal testing machine of United Co. according to ASTM D638, crosshead speed 5 mm / min, temperature 20 ± 2 ℃, relative humidity The experiment was performed under 60% conditions.

In the impact resistance test, the Notched Izod impact strength was measured using a Universal Impact Tester manufactured by Yasuda Seiki of Japan according to ASTM D256 at room temperature.

In addition, in order to observe the cross-section of the polyamide recycled resin / waste PVB of Example 3 and the polyamide recycled resin / waste PVB / SEBS-g-MA sheet of Example 3 according to the present invention (Scanning Electron Microscopy, manufactured by Philips Corporation) , SEM-515) and micrographs are shown in FIGS. 1 and 2.

TABLE 2

TABLE 3

Property

As can be seen from the results of the above experimental example, the analysis data of Notched Izod impact strength and elongation-tensile strength on blends of polyamide recycled resin and waste PVB are compared with pure polyamide recycled resin and raw materials as waste PVB content increases. It can be seen that the molding material exhibits a very high notch Izod impact strength and an excellent ductility which shows excellent elongation. Considering the recycling aspect and mechanical properties, PVB can be seen to be a very effective impact resistant polymer for polyamide-based raw materials and recycled resins. Since the molding material of the present invention has an interfacial adhesive force between the polyamide and the PVB, the impact resistance and the elongation characteristics are improved while having both the properties of the polyamide and the PVB.

Looking at the microstructure of the moldings observed through the scanning electron microscope, the SEM photograph after the impact test was given by notching in the direction perpendicular to the flow direction of the sheet, and the polyamide recycled resin / waste PVB (70/30) sheet of Example 3 was observed. The cross-section shows that the PVB particles in the dispersed phase are about 1.5 μm in size and are uniformly distributed in the spherical polyamide matrix, and there is an adhesive force between the regenerated polyamide matrix and the PVB interface. ) Phenomenon could be observed.

Looking at the cross-section of the polyamide recycled resin / waste PVB / SEBS-g-MA (70/25/5) blend of Example 10 of the present invention shown in Figure 2 compared to Figure 1, the wetting phenomenon is improved and close to the continuous form The particle size of the dispersed phase is also smaller. In addition, in FIG. 1, when the pulverized dispersed PVB was separated from the cross-section, the pupil was observed, but in FIG. 2, the adhesion of the interface was improved due to the morphology without the pupil.

In the materials shown in Examples 21 to 25 of the present invention, since the hydroxyl group contained in the waste PVB reacts with the silane group on the surface of the reinforcing fiber, the interfacial adhesion is increased, which is superior to that of the polyamide-based composite material reinforced with glass fiber. The impact property is shown.

Therefore, it can be seen that economic benefits can be obtained by recycling polyamide recycled resins instead of expensive polyamide raw materials, and impact resistance and mechanical properties can be greatly improved by adding compatibilizers and reinforcing fibers.

As can be seen from the above results, in view of the fact that the international necessity of automobile related parts recycling is emerging, the present invention conserves resources related to the environment, saves energy, and uses automobiles by recycling polyamide and polyvinyl butyral. It can be seen that it can contribute to the construction of technology base for parts recycling.

Claims (8)

In the polyamide resin composition containing a polyamide resin and a polyvinyl butyral component, (A) 30 to 90% by weight of polyamide recycled resin, (B) 20 wt% or less of polyamide raw material having an inherent viscosity of 0.5 to 2.5 dl / g, (C) 10 to 40% by weight of waste polyvinylbutyral component containing 10 to 35% of hydroxyl groups or (D) A polyamide resin composition using recycled products, characterized in that it contains one or more and 10% by weight or less selected from compatibilizers or reinforcing fibers. The polyamide resin composition according to claim 1, wherein the polyamide recycled resin is nylon 6, nylon 66 or nylon resin mixed with reinforcing fibers. The polyamide resin composition according to claim 1, wherein the waste polyvinyl butyral has a molecular weight of 55,000 to 200,000 and a hydroxyl group of 25 to 35%. The polyamide resin composition according to claim 1, wherein the polyamide resin composition contains a maleated thermoplastic elastomer as a compatibilizer. 5. The polyamide resin composition according to claim 4, wherein the maleated thermoplastic elastomer is maleated from 0.5 to 10% by weight relative to the block copolymer. The polyamide resin composition according to claim 1, wherein the polyamide resin composition contains at least one component selected from glass fibers and carbon fibers as reinforcing fibers. The polyamide resin composition according to claim 6, wherein the glass fiber has a density of 2.30 to 2.60 g / cm 3 and a diameter of the fiber of 7 to 20 µm. 8. The polyamide resin composition according to claim 6 or 7, wherein the glass fiber is surface treated with a silane coupling agent.