JP4488525B2 - Polymer composition - Google Patents

Description

  The present invention relates to a polymer composition and a vehicle body exterior part manufactured from the composition.

  These vehicle body exterior parts are suitable for withstanding the temperature of about 200 ° C. generated during cathodic dip coating without being deformed, and further, glass fibers are used to obtain an A class surface. Not added.

  In automobile manufacturing, car body exterior parts, such as bumpers or fenders, are usually manufactured from metal. However, in the case of minor damage, plastics are increasingly used because of weight savings and cost advantages. Fiber reinforced unsaturated polyesters and polyurethanes are used as thermosetting plastics. A common thermoplastic is elastomer-modified polypropylene for cost reasons. For optically and mechanically demanding applications, various polyester-based compositions and polymer blends based on polyphenylene oxide and polyamide are used.

  Car body exterior parts made of plastic can be painted separately from the metal car body (offline) or integrated into the car body painting process. The latter case is distinguished by whether the plastic parts are installed before (online) or after (inline) cathodic dip coating. In the case of on-line painting, temperatures in the range of 195 to 210 ° C. occur, which are predicated on the corresponding heat distortion resistance of the materials used.

  The shape stability of the material during heating can be confirmed by various methods. Shape stability HDT according to DIN 53461 achieves a defined droop (Durcbiegung) while heating a liquid heat transfer medium while raising the temperature uniformly and applying a certain medium force to the bending specimens deposited on both sides Temperature.

  The hot shape stability of Martens according to DIN 53462 is characterized by the temperature at which a specimen heated at a defined heating rate in air bends within a defined range under the action of force. The softening temperature of the Vicat according to DIN ISO 306 is a temperature at which the specified indenter uniformly enters the surface of the plastic specimen at a depth of 1 mm while being heated uniformly with a force of 10 or 50N.

  As a measure for the hot shape stability of car body exterior parts, the so-called heat sag test was proved to be a practical evaluation. In this case, a tensile test body having a thickness of 4 mm according to ISO 3167 manufactured by injection molding according to DIN ISO 294 is stretched horizontally in one direction, and the sag from the horizontal plane is measured in millimeters at a prescribed temperature for a prescribed time. To do.

  If metal parts and plastic parts are used in the car body at the same time, for cost reasons and because of color constancy, the plastic parts have a conventional undercoat and topcoat that is conventional for metal parts. I can imagine it easily.

  Conventional polymers, as already mentioned, are particularly hot shape-stable, especially when high low temperature impact resistance is required in conjunction with slight thermal linear expansion and class A surfaces. The properties do not satisfy the conditions of undercoating, that is, cathodic dip coating.

  In recent years, therefore, attempts have been made to develop correspondingly suitable polymer compositions, which are exemplified below.

  Thermoplastic polymer compositions are known, for example, from U.S. Pat. No. 3,337,792. Here, a polymer composition consisting of polyphenylene ether and polyamide is described, which has an improved flowability over pure polyphenylene oxide.

  However, the processability of such compositions, especially by injection molding, is still inferior at 10 g / min (280 ° C./5 kg) at the achievable MFR values. Based on the final poor glass transition temperature and amorphous properties of polyphenylene ether, the polymer composition according to US-A-3379792 has a slight stiffness level and poor durability at temperatures above 180 ° C. Have Coupled with limited fluidity, especially in the case of building parts that are relatively large and thin in wall thickness, lead to surface defects in the form of ripples, irregularities (Unruhe) and transfer (Abzeichnungen), which are plastic parts With expensive and costly post-processing.

Blend compositions based on syndiotactic polymers are known, for example, from WO 99/14273. Here, a composition consisting essentially of the following components is described:
(A) a syndiotactic monovinyl aromatic polymer,
(B) polyamide,
(C) a compatibilizer for (a) and (b),
(D) a rubbery elastomer,
(E) a domain-forming rubber and (f) a functionalized polyolefin rubber.

  However, conventional products made of these polymer materials have disadvantages in heat resistance at loads around 200 ° C. or higher. For example, in a heat sag test at 250 ° C. for 30 minutes, the deflection of the specimen from the horizontal plane exceeds 50 mm.

Known thermoplastic materials based on elastomer-modified polypropylene and polyester blends are far from meeting the temperature requirements of on-line paintable car exterior parts, and blends based on polyphenylene oxide and polyamide are insufficient. Absent. Furthermore, neither the fluidity nor the appearance is satisfactory for the field.
US-A-3379792 WO99 / 14273

  Therefore, the object of the present invention is that the deflection of the specimen from the horizontal plane is less than 15 mm in the heat sag test at 250 ° C./30 minutes, has a high surface quality, and has a high impact resistance and a low hot linear expansion coefficient. It is to provide a polymer composition suitable for the production of body parts, which is associated with rigidity and can be produced at low cost. In particular, the polymer composition of the vehicle body exterior part should have high fluidity in the melt.

According to the present invention, this problem is
(A) polyamide,
(B) a syndiotactic monovinyl aromatic homopolymer or copolymer;
Solved by a polymer composition comprising (C) a polystyrene-copolymer or polystyrene graft copolymer and (D) an impact modifier.

  The present invention is described in detail below.

  Component (A) of the polymer composition according to the present invention is contained in the polymer composition in an amount of up to 100 parts by weight and, as a polyamide-forming monomer, lactams such as ε-caprolactam, capryllactam, laurinlactam and Φnantractam ( Φnantlactam) as well as a mixture of these monomers. As other polyamide-forming monomers, dicarboxylic acids such as alkanedicarboxylic acids having 6 to 12 carbon atoms such as azelaic acid, pimelic acid, adipic acid, corkic acid, sebacic acid and terephthalic acid and isophthalic acid and diamines such as 4-12 Alkyl diamines having the following alkyl groups, such as tetramethylene diamine, hexamethylene diamine and octamethylene diamine or 2,2-bis (4-aminophenyl) -propane, bis (4-aminocyclohexyl) methane, m-xylylenediamine or Bis (4-aminophenyl) methane and combinations of diamine and dicarboxylic acid in any ratio to each other, eg hexamethylene diammonium adipate, tetramethylene diammonium adipate It can be used hexamethylene diammonium terephthalate.

  Particularly preferred polyamides are polyamide 6, polyamide 66, polyamide 46, polyamide MXD6 and mixtures of these polyamides.

  The syndiotactic monovinylaromatic homopolymer or copolymer (component B) may be a syndiotactic polystyrene homopolymer or copolymer, preferably containing 80-100% of syndiotactic dyad and 50,000-2500,000. And a homopolymer or copolymer having a melting point of 160-310 ° C. The mass proportion of component (B) may be 0.1 to 80 parts relative to component (A).

  Polystyrene copolymer (C) is poly (styrene-co-acrylonitrile) copolymer, poly (styrene-co-methylvinyloxazoline) copolymer, poly (styrene-co-maleic anhydride) copolymer, poly (styrene-co-methyl-vinyloxazoline). -Co-acrylonitrile) copolymer or poly (styrene-co-maleimide) copolymer. Furthermore, the polystyrene copolymer (C) may be a mixture of two or more of the aforementioned polymers.

  Component (C) may be a polystyrene graft copolymer resulting from grafting of maleic anhydride, itaconic anhydride or (meth) acrylic acid and their esters from syndiotactic polystyrene.

  The mass proportion of component (C) may be 0.1 to 50 parts with respect to component A.

  Particularly advantageous are poly (styrene-co-maleic imides) in which the maleic anhydride groups are only partially imidized and have a weight average molecular weight of 80000-200000. The unreacted maleic anhydride group content of the poly (styrene-co-maleic acid imide) copolymer may be 0.1 to 10 mol%, and the maleic imide group content is 0.1 to 50 mol. %, And the glass transition temperature is 150-195 ° C.

  Poly (styrene-co-maleimide) copolymers having a glass transition temperature of 195 ° C. are particularly advantageous.

  Component (C) of the polymer composition according to the invention in this case not only acts as a phase mediator for (A) and (B), but in particular also acts as a heat resistance improver. This significantly improves the heat resistance to around 200 ° C. or higher.

  The impact modifier (D) may be natural rubber, polybutadiene, polyisoprene, polyisobutylene, butadiene and / or copolymers of isoprene with styrene and other comonomers, hydrogenated copolymers and / or maleic anhydride, itaconic anhydride, ( It may be a copolymer resulting from the grafting of (meth) acrylic acid and esters thereof. The impact modifier (D) may be a graft rubber having a crosslinked elastomeric core made of butadiene, isoprene or alkyl acrylate and having a graft shell made of polystyrene. Non-polar or polar olefin homopolymers and copolymers such as ethylene-propylene-, ethylene-propylene-diene- and ethylene-octene- or ethylene-vinyl acetate-rubber or maleic anhydride, itaconic anhydride, (meth) acrylic acid and It may be nonpolar or polar olefin homopolymers and copolymers produced by grafting these esters. The impact modifier (D) is a carboxylic acid functionalized copolymer such as poly (ethene-co- (meth) acrylic acid) or poly (ethene-co-1-olefin-co- (meth) acrylic acid). Also included are copolymers in which the 1-olefin is an alkene or unsaturated (meth) acrylic acid ester having more than 4 atoms, the acid groups being partially neutralized by metal ions.

  Particularly advantageous are copolymers of butadiene and styrene functionalized by grafting with maleic anhydride, nonpolar or polar olefin homopolymers and copolymers produced by grafting with maleic anhydride, and acid groups partially Carboxylic acid functionalized copolymers that have been neutralized by metal ions, such as poly (ethene-co- (meth) acrylic acid) or poly (ethene-co-1-olefin-co- (meth) acrylic acid). .

  The mass proportion of component (D) may be 0.1 to 50 parts with respect to component (A).

  In some cases, the polymer composition of the car body exterior component is up to 5 parts by weight of the lubricant or processing aid, up to 5 parts by weight of the pigment, up to 2 parts by weight of the nucleating agent, and 1 part by weight of the stabilizer. Up to 2 parts by weight of foaming agent, up to 2 parts by weight of antistatic agent, up to 100 parts by weight of process oil, up to 100 parts by weight of filler and / or flame retardant, up to 200 parts by weight of additives You may contain.

  By adding a conductive additive to the polymer or polymer composition, it is possible to paint polymer parts with an electrostatic field. In this case, the charged paint part follows the electric lines of force from the paint gun to the support to be painted. In this case, it is advantageous to apply the paint in a particularly uniform manner, ie to avoid “Wolkenbildung” and to significantly reduce the so-called overspray of the paint. Since the conductive additive can significantly affect the mechanical properties of the polymer composition, the method technique selected for its selection and its mixing is important.

Preferred conductive additives are conductive carbon black, conductive graphite, metal particles, carbon-nanotubes, PAN-carbon fibers, nickel-plated carbon fibers, recycled carbon fibers, metal-coated glass fibers or ceramic fibers (whiskers). . Especially preference is given to nitrogen adsorption amount of particle size and 30~1500m ² / g of 10 to 60 nm, conductive carbon black having a DBP adsorption of 40~450cm ³ / 100g (dibutyl phthalate adsorption = oil-absorbing) It is.

  In this case, the addition of the conductive carbon black can be carried out in the form of pure powder / beads or can be carried out with a precursor compound of conductive carbon black based on component (A).

  As fillers, for example magnesium hydroxide, calcium carbonate, talc, wollastonite, silicic acid and silicates having an ionic layered charge, modified by cation exchange or anion exchange, are advantageously used in oils or solid components. Suspend in water before use.

  Glass fibers can also be added in special cases.

  The polymer composition for car body parts according to the invention can be produced in a known manner by mixing and heating the individual components, preferably in an aftertreatment device under the action of shear forces. The polymer composition can be processed to produce molded parts or semi-finished products by extrusion or injection molding.

  The polymer composition according to the invention is advantageously used in the assembly of automobiles for producing car body exterior parts. Such vehicle body exterior parts include fenders, bumpers, side parts, tank valves and / or door exterior exteriors. The polymer composition according to the invention is preferably produced by an injection molding process and / or by extrusion blow molding (Gasinnendruckverfahren).

  The following examples illustrate the invention in detail, but the invention should not be limited to these examples.

  The composition is described as a weight percentage with respect to 100 parts by weight of component (A) and is as follows in the following examples or comparative examples:

［１］例１のポリアミド：ポリアミド６６、融点２６０℃、比重１．１２ｇ／ｃｍ^３、
［２］例２のポリアミド：ポリアミド４６、融点２９５℃、比重１．１８ｇ／ｃｍ^３、
［３］シンジオタクチックポリスチレン：Ｍｗ＝３０００００、シンジオタクティシティー９６％、
［４］ポリスチレンコポリマー：ポリ（スチレン−コ−マレイン酸イミド）、Ｍｗ＝１５００００、マレインイミド基の含有率３９モル％、ガラス転移温度１９５℃、
［５］耐衝撃性改良剤：スチレン−エチレン／ブタジエン−スチレン−トリブロックコポリマー、ＭＦＲ［ｇ／１０分］２３０℃／５ｋｇで１より小、スチレン／ＥＢ比３０／７０、
［６］耐衝撃性改良剤：無水マレイン酸グラフトエチレン−オクテン−コポリマー、ＭＦＲ［ｇ／１０分］１９０℃／２．１６ｋｇで１．２、平均的なグラフト度、
［７］比較例２のポリアミド：ポリアミド６、融点２２０℃、比重１．１０ｇ／ｃｍ^３、
［８］ＰＰＥ：ポリフェニレンエーテル、粘度０．４０ｄｌ／ｇ、
［９］耐衝撃性改良剤：無水マレイン酸グラフトスチレン−エチレン／ブタジエン−スチレン−トリブロックコポリマー、ＭＦＲ［ｇ／１０分］２３０℃／５ｋｇで２２、スチレン／ＥＢ比３０／７０、
［１０］Ｍｏｎｓａｎｔｏ社のＴｒｉａｘ １１８０。

[1] Polyamide of Example 1: Polyamide 66, melting point 260 ° C., specific gravity 1.12 g / cm ³ ,
[2] Polyamide of Example 2: Polyamide 46, melting point 295 ° C., specific gravity 1.18 g / cm ³ ,
[3] Syndiotactic polystyrene: Mw = 300000, syndiotacticity 96%,
[4] Polystyrene copolymer: poly (styrene-co-maleimide), Mw = 150,000, maleimide content of 39 mol%, glass transition temperature 195 ° C.
[5] Impact modifier: styrene-ethylene / butadiene-styrene-triblock copolymer, MFR [g / 10 min] less than 1 at 230 ° C./5 kg, styrene / EB ratio 30/70,
[6] Impact modifier: maleic anhydride grafted ethylene-octene-copolymer, MFR [g / 10 min] 1.2 at 190 ° C./2.16 kg, average degree of grafting,
[7] Polyamide of Comparative Example 2: Polyamide 6, melting point 220 ° C., specific gravity 1.10 g / cm ³ ,
[8] PPE: polyphenylene ether, viscosity 0.40 dl / g,
[9] Impact modifier: maleic anhydride grafted styrene-ethylene / butadiene-styrene-triblock copolymer, MFR [g / 10 min] 22 at 230 ° C./5 kg, styrene / EB ratio 30/70,
[10] Monsanto's Triax 1180.

Comparative Example 2:
In a twin screw extruder with a feeding device for granules, granulated syndiotactic polystyrene [3], polyamide [7], impact modifier [6], ethylene diluted in oil at temperatures above 270 ° C. -Octene-copolymer and fumaric acid grafted PPO were fed. The mixture was melted, extruded and cut. The resulting thermoplastic mixture had the properties described in the table.

Example 1:
Syndiotactic polystyrene [3], polystyrene copolymer [4], polyamide [1] and impact modifier [5] in the form of granules at a temperature higher than 270 ° C. in a twin screw extruder having a feeder for granules Supplied. The mixture was melted, extruded and cut. The resulting thermoplastic mixture had the properties described in the table.

Example 2:
Syndiotactic polystyrene [3], polystyrene copolymer [4], polyamide [1] and impact modifier [6] in the form of granules at a temperature higher than 270 ° C. in a twin screw extruder having a feeder for granules Supplied. The mixture was melted, extruded and cut. The resulting thermoplastic mixture had the properties described in the table.

Example 3:
Syndiotactic polystyrene [3], polystyrene copolymer [4], polyamide [2] and impact modifier [5] in the form of granules at a temperature higher than 295 ° C. in a twin screw extruder having a feeder for granules Supplied. The mixture was melted, extruded and cut. The resulting thermoplastic mixture had the properties described in the table.

Example 4:
Syndiotactic polystyrene [3], polystyrene copolymer [4], polyamide [2] and impact modifier [6] in the form of granules at a temperature higher than 295 ° C. in a twin screw extruder having a feeder for granules Supplied. The mixture was melted, extruded and cut. The resulting thermoplastic mixture had the properties described in the table.

  Table 1 below shows the mechanical properties of the compositions according to the invention, and Table 2 shows the mechanical properties of the compositions according to Comparative Examples 1-3.

Claims (17)

(A) 100 parts by mass of polyamide,
(B) 0.1-80 parts by weight of syndiotactic monovinyl aromatic homopolymer or copolymer,
(C) 0.1-50 parts by mass of a polystyrene copolymer or polystyrene graft copolymer,
(D) 0.1-50 parts by mass of impact resistance improver
(Wherein the mass proportions of components (B), (C) and (D) are each for component (A)) and have a sag of less than 15 mm in a heat sag test at 250 ° C. for 30 minutes A polymer composition suitable for producing car body exterior parts. Component (A) is polyamide 6, polyamide 66, polyamide 46, from the group of polyamide MXD6, or are mixtures of these polyamides, claim 1 polymer composition. Component (B) contains 80% to 100% of syndiotactic dyads, syndiotactic polystyrene having a number average molecular weight and a melting point of 160-310 ° C. of 50,000 to 2,500,000 - a homopolymer or a copolymer, according to claim 1 The polymer composition described. Component (C) is a poly (styrene-co-acrylonitrile) copolymer, poly (styrene-co-methylvinyloxazoline) copolymer, poly (styrene-co-maleic anhydride) copolymer, poly (styrene-co-methylvinyloxazoline- co - acrylonitrile) copolymers, poly (styrene - co - maleic acid imide) group of the copolymer, or are mixtures of these copolymers, according to claim 1 polymer composition. In component (C), or maleic acid or itaconic anhydride (meth) polystyrene from syndiotactic polystyrene by grafting of acrylic acid and their esters - graft copolymers occurs claim 1 polymer composition. Component (D) is produced by grafting with copolymers of butadiene and / or isoprene and styrene and other comonomers, hydrogenation products and / or maleic anhydride, itaconic anhydride, (meth) acrylic acid and esters thereof. product are: maleic acid, itaconic anhydride, (meth) acrylic acid and olefin homopolymers and copolymers of non-polar or polar occurs by grafting with these esters or carboxylic acid functionalized copolymer over, The polymer composition according to claim 1 , wherein the polymer group is selected from the group, wherein the acid groups are partially neutralized by metal ions. 7. The polymer composition of claim 6, wherein the carboxylic acid functionalized copolymer is poly (ethene-co (meth) acrylic acid) or poly (ethene-co-1-olefin-co- (meth) acrylic acid). . 6. A polymer composition according to claim 5 , wherein component (C) is a poly (styrene-co-maleic imide) copolymer having one residue of unreacted maleic anhydride groups.   The polymer composition according to claim 8, wherein the content of unreacted maleic anhydride groups in the poly (styrene-co-maleic imide) copolymer is 0.1 to 10 mol%.   The polymer composition according to claim 8 or 9, wherein the poly (styrene-co-maleimide) copolymer has a glass transition temperature of 150 to 195 ° C.   Additionally, up to 5 parts by weight of lubricant or processing aid, up to 5 parts by weight of pigment, up to 2 parts by weight of nucleating agent, up to 1 part by weight of stabilizer, up to 2 parts by weight of foaming agent, antistatic agent 2 to 2 parts by weight, process oil to 100 parts by weight, fillers and / or flame retardants to 100 parts by weight, containing up to 200 parts by weight of additives to component (A). The polymer composition according to any one of 1 to 10. The polymer composition according to any one of claims 1 to 10, which additionally contains glass fibers. The polymer composition according to any one of claims 1 to 11, further comprising a conductive additive. 14. Polymer composition according to claim 13, wherein the conductive additive is a conductive carbon black having a particle size of 10-60 nm, a nitrogen adsorption of 30-1500 m < ² > / g and a dibutyl phthalate adsorption of 40-450 cm < ³ > / 100 g. object. Use of the polymer composition according to any one of claims 1 to 14 for producing car body exterior parts in automobile manufacture. 16. Use according to claim 15 , wherein the car body exterior part is a fender, bumper, side part, tank valve, sill and / or door exterior exterior. More producing body exterior part in injection molding and / or extrusion blow molding, the use of claim 15 or 16, wherein.