Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L77/00—Compositions of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Compositions of derivatives of such polymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L77/00—Compositions of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Compositions of derivatives of such polymers
  • C08L77/02—Polyamides derived from omega-amino carboxylic acids or from lactams thereof
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L77/00—Compositions of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Compositions of derivatives of such polymers
  • C08L77/06—Polyamides derived from polyamines and polycarboxylic acids
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
  • C08L67/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds
  • C08L67/03—Polyesters derived from dicarboxylic acids and dihydroxy compounds the dicarboxylic acids and dihydroxy compounds having the carboxyl- and the hydroxy groups directly linked to aromatic rings
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
  • C08L67/04—Polyesters derived from hydroxycarboxylic acids, e.g. lactones

Definitions

• the invention relates to a polyamide moulding composition comprising Nylon-6 and a fibrous reinforcing agent.
• Nylon-6 is a widely used engineering plastic, having good mechanical and thermal properties. Fibrous reinforcing agents are generally added to increase the mechanical strength and modulus.
• a disadvantage of the polyamide moulding composition comprising Nylon-6 and a fibrous reinforcing agent is that a moulded part prepared from said composition tends to warp.
• the extent of warpage can be too large and the part does not comply anymore with the required dimensional accuracy.
• the aim of the invention is to provide a Nylon-6 moulding composition, which does not have these disadvantages or in a lesser extent.
• composition according to the invention comprising 30-75 wt.% nylon 6, 9-50 wt% fibrous reinforcing agent and 1-20 wt.% of a thermotropic liquid crystalline polymer (TLCP), the weight percentages being relative to the total weight of the composition.
• TLCP thermotropic liquid crystalline polymer
• the advantage of the composition according to the invention is that moulded parts made of the composition show less warpage and more precise dimensions than moulded parts made of a corresponding composition without the TLCP
• the reduced warpage also allows more freedom of design for the moulded part as well as of moulded parts having thinner wall sections. Therefore, the composition according to the invention is particularly suitable for preparing large and thin-walled moulded products or moulded products with more precise dimension requirements.
• the Nylon-6 that can be used in the composition according to the invention can be any Nylon-6 polymer suitable for use in fiber reinforced moulding compositions for preparing moulded articles.
• Nylon 7 6 is herein understood to be a polyamide consisting essentially of monomeric units derived from ⁇ -caprolactam.
• the Nylon-6 in the composition according to the invention comprises at least 90 wt.% monomeric units, derived from ⁇ -caprolactam, preferably at least 95 wt.% ⁇ -caprolactam.
• Nylon-6 consisting essentially of monomeric units derived from ⁇ -caprolactam may optionally also comprise other monomer units, such as monomeric units derived from monomers including other lactam monomers (such as lauryllactam), or the ⁇ , ⁇ -aminocarboxylic acid equivalent thereof (such as r ⁇ -amino lauric acid), diamines and/or dicarboxylic acids.
• the other monomer units may also comprise monomeric units derived from branching agents.
• Branching agents when used in the preparation of Nylon-6, are typically used in very small amounts. Suitable branching agents are, for example, trifunctional amines and trifunctional carboxylic acids.
• the other monomeric units may be also be derived from aliphatic and /or aromatic components.
• any known component suitable for the preparation of polyamides may be used.
• suitable aliphatic diamines that can be used as basis for a monomeric unit in the Nylon-6 according to the invention are 1 ,4-butanediamine and 1 ,6-hexanediamine.
• An example of a suitable aliphatic dicarboxylic acid that can be used is adipic acid.
• An example of a suitable aromatic diamine that can be used is 1 ,4-diaminomethylbenzene.
• Example of a suitable aromatic dicarboxylic acid that can be used is isophthalic acid and therephatalic acid.
• any reinforcing agent known in the art suitable for use in polyamide moulding compositions may be used.
• Such fibrous reinforcing agent typically has a short fiber length, allowing the moulding composition to be processed in a melt processing step.
• the length of the fiber may be in the range of millimeters, for example, 1 to 20 mm, but it may also be in the ⁇ m range, for example 50-500 ⁇ m and even in the nm range, for example 100- 5000 nm.
• Suitable fibrous reinforcing agents are, for example, glass fibers (GF), carbon fibers (CF), Kevlar fibers or whiskers.
• Suitable whiskers are for example, inorganic whiskers, such as K 2 Ti 6 O ⁇ 3 whiskers.
• the TLCP suitable for use in the composition of the present invention may be any TLCP that is immiscible or partially miscible with nylon 6.
• Particular suitable TLCPs are TLCPs having a melting temperature of 190-360°C, more preferably 230-300 °C.
• the TLCP that is comprised by the composition according to the invention is a main-chain aromatic copolyester.
• main-chain liquid crystalline polymer is normally used in the field of liquid crystalline polymers and is understood to be a liquid crystalline polymer comprising a main chain and liquid crystalline polymer segments, wherein the liquid crystalline polymer segments are comprised by the main chain (see for instance H. Finkelman in Materials Science Series / Polymer Liquid Crystals, A. Ciferri, W.R. Krigbaum and R.R. Meyer, editors, Acadamic Press, New York, 1982, page 36; and G.W. Gray and P.A. Windsor, editors, Liquid Crystals & Plastic Crystals, Vol. I, Wiley, New York, 1974).
• the main-chain aromatic copolyester preferably is a copolyester chosen from the group consisting of copolyesters of 2,6-hydroxynaphthoic acid (HNA) and p-hydroxybenzoic acid (PHB) (e.g., commercially known as Vectra A900 and VectraA950 manufactured by Ticona Co., USA), copolyester-amides of 6-hydroxy-2-naphthoic acid (HNA), terephthalic acid (TA), and aminophenol (APO), (e.g., commercially known as Vectra B900, and Vectra B950 manufactured by Ticona Co, USA), copolyesters of p-hydroxybenzoic acid (PHB) and poly(ethylene terephthalate) (PET) (e.g., commercially known as LC 3000, LC 5000 manufactured by Unitika Co., Japan; X7G manufactured by Eastman Co., USA), and copolymers of terephthalic acid (TA),
• HNA 2,6-hydroxynaphthoic acid
• PHB p-hydroxybenzoic acid
• the composition according to the invention may optionally also comprise at least one additive.
• the at least one additive that may be comprised in the composition according to the invention may be any additive generally used in polyamide moulding compositions and which can lend desirable qualities to the composition.
• Such additives include, for example, flame retardants, nucleating agents, antioxidants, stabilizers, colorants, dyes, pigments, plasticizers, non-fibrous fillers, non-fibrous reinforcing agents, processing aids and polymers other than Nylon-6, such as impact modifiers and compatibilizers.
• the composition according to the invention may comprise the at least one additive in an amount which can vary over a large range.
• the composition according to the invention consists of a) 30-75 wt.% nylon-6, b) 9-50 wt% fibrous reinforcing agent c) 1 -20 wt.% thermotropic liquid crystalline polymer (TLCP), d) 0.1 -60 wt% of at least one additive chosen form the group of flame retardants, nucleating agents, antioxidants, stabilizers, colorants, dyes, pigments, plasticizers, non-fibrous fillers, non-fibrous reinforcing agents, and processing aids the weight percentages being relative to the total weight of the composition.
• TLCP thermotropic liquid crystalline polymer
• composition comprises between 20 to 40 % by weight, relative to the weight of the composition, of the at least one additive.
• the moulding composition according to the invention containing a fibrous reinforcing agent and a TLCP can be produced by conventional melt blending techniques involving melt-blending of the respective components in the required amounts.
• any apparatus suitable for that process may be used.
• suitable for that process may be used.
• the TLCP and the Nylon-6 may be fed to the melt-blending apparatus, for example, in the form of pellets or a melt.
• the TLCP and the Nylon-6 are added in the form of a pellet blend.
• TLCP is used as one component in a polymeric formulation.
• one or more other polymers e.g. a compatibilizer, are blended with the TLCP prior to blending with the Nylon-6.
• the reinforcing agent is preferably added to the melt of the TLCP and the Nylon-6.
• the invention also relates to a process for preparing a moulded product comprising melt-processing and moulding of the composition according to the invention.
• melt-processing and moulding of the composition according to the invention conventional melt-processing and moulding techniques, involving the use of any apparatus suitable for that process, may be used.
• melt-processing and moulding equipment such as single-screw extruders and twin-screw extruders.
• the invention further relates to a moulded product obtainable by the moulding process according to the invention.
• the advantage thereof is that it shows less warpage compared to a corresponding moulded product made by a process wherein the composition that is moulded is a corresponding polyamide moulding composition comprising Nylon-6 and a fibrous reinforcing component which does not comprise a TLCP.
• the moulded product preferably is a thin walled product such as thin-walled products for automotive applications and a connector for E&E applications.
• the TLCP used in the examples is Vectra A950, a copolyester with a melt temperature of 280°C.
• the Nylon-6 used was a standard grade Nylon 6 with a relative viscosity value of 2.2, and is denoted as PA6.
• the glass fibers used was a standard grade for use in polyamide moulding compositions, and is denoted as GF. All the materials, Nylon-6, glass fibers and TLCP, were carefully dried at 90°C under vacuum for at least 24 hours prior to use.
• Example 1 A composition of PA6/GF/TLCP, weight ratio 65/30/5, was prepared by feeding the PA6 and TLCP components via a hopper to a Werner & Pfleiderer ZSK30 twin-screw extruder, melt-blending the PA6 and TLCP in the extruder, thereby forming a polymer melt, dosing the glass fibers to the polymer melt and mixing the polymer melt and the glass fibers in the extruder, thereby forming a melt of a molding composition and extruding the melt of the molding composition from a die.
• the temperatures of the barrel sections of the extruder, in the order from the hopper to the die, were set at 280, 310, 310, 280, 280, 280, 280 and 280°C.
• the rotor speed was fixed at 200 rpm, the throughput was 10 kg/hour.
• the extrudate was cooled with water and pelletized.
• the pelletized material was injection moulded with a Kraus Maffei
• KM 120 extruder in a mould with dimensions 60 mm (length) x 60 mm (width) x 1 mm (thickness).
• the temperature of the extruder was set at 250-280°C to have a melt temperature at the die of 280°C.
• the temperature of the mould was set at 80°C.
• the flat square moulded part was ejected after 30 seconds and left to cool to room temperature.
• a composition of PA6/GF, weight ratio 70/30 was prepared in the same manner as the composition of Example I. Form the resulting pelletized extrudate a flat square moulded part was prepared in the same way as Example I. Warpage test.

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Reinforced Plastic Materials (AREA)

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Citations (5)

• 2002
  • 2002-09-13 CN CN 02143127 patent/CN1187410C/zh not_active Expired - Fee Related
• 2003
  • 2003-09-11 AU AU2003269714A patent/AU2003269714A1/en not_active Abandoned
  • 2003-09-11 WO PCT/NL2003/000631 patent/WO2004024821A1/en not_active Application Discontinuation

Patent Citations (5)

Non-Patent Citations (2)

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