WO1995004782A1 - A method for preparing polymer blends which contain in situ liquid crystal polymer fibers - Google Patents

A method for preparing polymer blends which contain in situ liquid crystal polymer fibers Download PDF

Info

Publication number
WO1995004782A1
WO1995004782A1 PCT/FI1994/000345 FI9400345W WO9504782A1 WO 1995004782 A1 WO1995004782 A1 WO 1995004782A1 FI 9400345 W FI9400345 W FI 9400345W WO 9504782 A1 WO9504782 A1 WO 9504782A1
Authority
WO
WIPO (PCT)
Prior art keywords
liquid crystal
polymer
crystal polymer
concentrate
fibers
Prior art date
Application number
PCT/FI1994/000345
Other languages
French (fr)
Inventor
Esa Suokas
Taina Aalto
Christer BERGSTRÖM
Original Assignee
Neste Oy
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Neste Oy filed Critical Neste Oy
Publication of WO1995004782A1 publication Critical patent/WO1995004782A1/en

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
    • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
    • C08L23/10—Homopolymers or copolymers of propene
    • C08L23/12—Polypropene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J3/00—Processes of treating or compounding macromolecular substances
    • C08J3/005—Processes for mixing polymers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L101/00—Compositions of unspecified macromolecular compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2205/00—Polymer mixtures characterised by other features
    • C08L2205/12—Polymer mixtures characterised by other features containing additives being liquid crystalline or anisotropic in the melt

Definitions

  • the invention relates to a two-step process for the preparation of a mixture of a liquid crystal polymer and a matrix polymer.
  • Liquid crystal polymers are polymers which, when molten, are intermediate forms of a solid-state substance and a liquid.
  • the liquid crystal phase is indeed called a 'meso- morphic phase' or an ' amsotropic phase', since liquid crystal polymers are macroscopical- ly fluid when molten. Microscopically they have a regular structure, as have crystals.
  • Liquid crystal polymers are made up of stiff linear or spiral molecule chains. Their principal components are aromatic cyclic structures, which are usually interlinked by ester, ether or amide bonds. Liquid crystal polymers spontaneously arranging in molten state are called thermotropic and those arranging in liquid state are called lyotropic. The more linear and the more tactic the molecules of liquid crystal polymers, the more com ⁇ pletely and the more rapidly they will crystallize. Liquid crystal resins are usually typical semicrystalline polymers, but their molecules solidified into a glass state are not oriented randomly but monoaxially, i.e. nematically.
  • Thermotropic liquid crystal resins constitute a very wide polymer group, in which the properties of the various types differ significantly from each other. On the basis of their heat deflection temperature, liquid crystal polymers can be divided into three categories.
  • the liquid crystal polymers belonging to the first category crystallize almost completely, and so their heat resistance is very high.
  • Commercial Xydar Amoco Premark
  • LC polymers of the first category are high owing to rectilinear molecule chains.
  • thermotropic polymers can be processed by conven ⁇ tional melt-molding methods for resins, for example by injection molding.
  • Xydar Owing to its liquid crystal behavior, Xydar has a viscosity of approx. 1000 Pa s, the measuring temperature being 430 °C and the measuring shear rate being 1000 s "1 . Since the LC transition, analogous to melting, of the thermotropic polymers of the first category takes place at a very high temperature (Xydar SRT-300, 421 °C), they must be processed by using modified extruders and injectors.
  • thermotropic liquid crystal polymers of the second category are synthesized from monomers the conformations of which inhibit dense packing of the molecule chains and at the same time their excessive crystallization, and thus their LC transition temperature drops.
  • These thermotropic polymers are typical semicrystalline thermoplastic resins, but their molecules, solidified into an amorphous glass state, are not oriented randomly but monoaxially, i.e. nematically.
  • the heat resistance of the thermotropic polymers of the second category is not determined according to the LC glass transition temperature, because the heat deflection temperature of those liquid crystal polymers is in general closer to the temperature of liquid crystal transition than that of glass transition.
  • the best known commercial polymer is Vectra A900 (Hoechst Celanese) synthesized from p-hydr- oxybenzoic and 6-hydroxy-2-naphthoic acids, having an LC transition point of 280 °C, a heat deflection temperature of 180 °C (1.82 MPa), and a typical degree of crystallinity of 20 %.
  • the viscosity of the said liquid crystal copolyester at a temperature of 300 °C and at a shear rate of lOOO "1 is 60 Pa s.
  • thermotropic polymers of the third category has been improved by adding to a stiff molecule a flexible unit, for example a methylene chain, whereby their crystallinity and heat deflection temperature drop but their tenacity increases.
  • a flexible unit for example a methylene chain
  • An example of commercial polymers of this type is X7-G (Eastman Kodak), synthesized from p- acetoxybenzoic acid and polyethylene terephthalate. Its viscosity is approx. 10 Pa s, the temperature being 260 °C and the shear rate 1000 s "1 .
  • Conventional polymers among others polyethylene and polypropylene, are made up of flexible molecule chains which are grouped either randomly or in an ordered manner. Within the amorphous range the molecule chains are located completely at random, whereas within the ordered range the polymers are crystallized as three-dimensional structures. Amorphous polymers are isotropic both at the macro level and at the micro level. Thermoplastics are usually semicrystalline polymers. Semicrystalline and crystalline (100 %) conventional thermoplastics are microscopically amsotropic but macroscopically isotropic.
  • stiff anisotropic liquid crystal polymers are superior to those of conventional isotropic resins. They have a lower viscosity, better mechanical properties, a lower linear coefficient of thermal expansion (CTE), as well as better resistance to heat and chemicals.
  • CTE linear coefficient of thermal expansion
  • liquid crystal polymers are made up of stiff linear molecules, at the macro level they are comparable to carbon fibers or glass fibers. When liquid crystal polymers are mixed with conventional isotropic polymers, their stiff molecules will reinforce the matrix material in the same manner as do carbon fibers or glass fibers. Liquid crystal polymers and conventional matrix resins are in general not miscible with each other at the molecular level; they form a two-phase system. At rest a liquid crystal polymer is dispersed as spherical blocks in an isotropic matrix. When this polymer mixture is subjected to a shearing and/or stretching flow, the block-like liquid crystal areas stretch in the field of shearing or stretching stress, since the stiff LC molecules easily slide one past another.
  • the liquid crystalline areas turn into in-situ fibers or sheets.
  • the components In order for the relative movement of the LC polymer and the matrix resin to be possible, the components must not mix with each other, and they must not be comple ⁇ tely compatible. Furthermore, the viscosity of the liquid crystal polymer must be lower than that of the isotropic matrix.
  • the present invention relates to mixtures of a liquid crystal polymer and a matrix resin, prepared in two steps.
  • a liquid crystal polymer dominant concentrate is prepared in which the matrix polymer consists of one of more conventional polymers (e.g. polypropylene).
  • the proportion of liquid crystal polymer in the concentrate is at minimum 60 %.
  • the processing device itself such as a compounder (in situ).
  • the formed concentrate bar is cut into the desired length, whereafter it is fed into a second extruder.
  • the temperature of this device is set at a level below the melting point of the liquid crystal polymer, and so the LC fibers formed in the first compounding step will not melt.
  • additives such as viscosity reducers, bonding agents, and compatibili- zers may be fed into the extruder.
  • the completed product is granulated, which enables further processing to be carried out, for example, by injection molding.
  • flexible situ liquid crystal fibers arrive in a stretching and shearing flow field in the screw and mold of the processing machine, they become deformed, only the microstructure beco ⁇ ming fibrillated.
  • the unmelted liquid crystal polymer fibers will not break in the way stiff glass or carbon fibers do.
  • the length of the granulated liquid crystal fibers will remain unchanged, but their flexibility will increase owing to fibrillation, and therefore they will twist into a tangle as the melt flows in the flow conduits and the mold cavity.
  • a piece thus injection molded will be more isotropic than pieces made using stiff and brittle reinforcements.
  • a two-step preparation of a mixture of a liquid crystal polymer and a matrix polymer is also described in EP application publication 499387. According to it, also, first a 'concentrate' is made which contains more than 2 % liquid crystal polymer, and in the second step the mixture is diluted to the degree that the content of liquid crystal polymer will be less than 2 % . However, the melt-mixing temperatures in both steps are such that the liquid crystal polymer will not melt, i.e. the process does not aim at forming in-sifa fibers.
  • the LCP content in the concentrate is more than 60 % by weight, preferably 70-90 % by weight.
  • the matrix polymer may be any conventional polymer (e.g. polyethylene, polypropylene), engineering polymer (e.g. polyamide, polyethylene terephthalate), elastomer (e.g. EPDM and SEBS), or a lower-melting aromatic polymer (e.g. HB A/PET).
  • the chemical structure of the matrix resin is not limited to homopolymers; also copolymers, which may be block-structured, random structured or branched, are possible.
  • the molar mass distributions and the polymer modality are selected according to the targeted application. Of course, mixtures of two or more polymers may also be used.
  • a liquid crystal polymer of the first, second or third category, or various mixtures thereof, may be used as the reinforcement.
  • the concentrate containing a liquid crystal polymer is diluted either with the same matrix resin as in the first compounding, or with a different one.
  • the zone temperatures in the processing machine such as a single- or twin-screw extruder, must be set so that the temperature of the molten compound will not exceed the melting point of the liquid crystal polymer fiberized in the preceding step.
  • the diluted mixture containing a liquid crystal polymer is run through the nozzle of the processing machine. Thereafter the formed extrusion profile is cooled and granulated, according to the intended use, into either short or long pellets.
  • the content of liquid crystal polymer can be diluted to 5-60 % by weight.
  • Additives may also be added during the diluting step to the mixture containing a liquid crystal polymer.
  • the additives it is possible, for example, to improve adhesion between the LC reinforcement and the matrix resin, mainly with respect to the solid liquid crystal fibers.
  • compatibilizers it is also possible to enhance the interactions between com ⁇ ponents of an immiscible and incompatible polymer mixture by means of compatibilizers.
  • Compatibilizing may be based on functionalized doping components, polymeric compatibi ⁇ lizers, or small-molecular compatibilizing compounds. Compatibilizing may be carried out during the diluting step, but often preferably already in connection with the preparation of the concentrate.
  • the diluting step it is also possible to improve the flow properties of the doped compound by using agents which reduce the viscosity of the polymer system, such as small-molecular chemicals or a second crystal polymer, which melts at a lower temperature.
  • agents which reduce the viscosity of the polymer system such as small-molecular chemicals or a second crystal polymer, which melts at a lower temperature.
  • Mineral fillers e.g. chalk and talcum
  • organic compounds e.g. carbon fiber and carbon black or PET staple
  • inorganic materials e.g. glass fiber and silica derivatives in whisker form
  • the diluted concentrate containing a liquid crystal polymer is processed to its final form according to the intended application, for example, by injection molding, pipe extrusion, blow molding or thermoforming.
  • the zone temperatures of the processing machine e.g. an injector
  • the zone temperatures of the processing machine must be set in such a manner that the temperature of the molten compound will not exceed the melting point of the fiberized liquid crystal polymer. This ensures that the in-sifa LC fibers are retained all the way to the end product. Since in-situ liquid crystal fibers are fibrillized in a shearing and stretching field, they become more flexible.
  • LC fibers are more isotropically oriented by the deformation differences appearing in the flow of the compound; this is also reflected in the properties of the end product/piece.
  • a matrix material can be reinforced more effectively than by using, for example, stiff carbon or glass staple fibers, since, owing to fibrillation, the flexibility of the liquid crystalline fibers is increased. Owing to the said mechanism, the length of the LC fibers will remain unchanged in the processing step, usually at a value higher than the critical value, contrary to that of carbon or glass fibers, which become ground into shorter units in flow fields.
  • the process of the invention provides, over in-sifa LC fibers formed in one processing step, the advantage that the diameter and length of the fiber can be adjusted so as to be better suited for the end application. Since in the first step of the invention the material is a concentrate in which the dominating component is a liquid crystal polymer, it will become better fiberized and better oriented under shearing and stretching deformation than will a final compound containing a larger amount of a conventional isotropic resin. Since in the second step the in-sifa LC fibers already formed are no longer melted, their length will not change. This leads to a reinforcement which is more isotropic than could be achieved by using an LC melt only.
  • the interface between the solid liquid crystal fibers and the matrix plastic is well-defined, which enables bonding agents to be used more effectively, since they can be linked by chemical bonds to the forming in-sifa LC fibers already in the first reactive molding step.
  • the necessary additives e.g. bonding agents, compatibilizers and stabilizers, are fed into the process in either the first or the second step of the invention, depending on the reactive components and reaction kinetics used.
  • Homopolypropylene VB65 50B (Neste Oy Chemicals) was selected as the matrix material and Vectra R A950 (Hoechst Celanese), which is a copolymer of p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid, as the liquid crystal polymer.
  • the melting point of the polypropylene used is 164 °C and that of the fully aromatic copolyester is 280 °C.
  • the said components were mixed in the form of granulates, whereafter the mixture was dried for 10 hours at 80 °C. In the concentrate the proportion of liquid crystal polymer was 80 % by weight and that of polypropylene 20 % by weight.
  • the dried component mixture was compounded in a twin-screw extruder, Berstorff ZE 25 x 33 D, and the screw geometry selected was the device manufacturer's "Polyblends 1 " configuration.
  • the zone temperafares were set as follows: 50-285-285-285-290-290-290- 290 °C.
  • the liquid crystal polymer was fiberized in the shearing and stret- ching field (in situ) of the nozzle of the twin-screw extruder.
  • the concentrate bar was cut into granules 10 mm long.
  • Example 2 Dilution and injection molding of a polypropylene/liquid crystal polymer mixture
  • the prepared concentrate was diluted with the matrix polymer of Example 1, PP VB65 50B (Neste Oy Chemicals).
  • the mixture contained concentrate 40 % by weight and diluting polymer 60 % by weight, and thus the final proportion of polypropylene was 68 % by weight and the proportion of liquid crystal polymer Vectra R A950 was 32 % by weight.
  • the diluted mixture was compounded in a twin-screw extruder, Berstorff ZE 25 x 33 D, and the screw geometry selected was the device manufacturer's "Polyblends 1" configura- tion.
  • the zone temperatures were set as follows: 50-200-200-200-200-200-200-200 °C.
  • the granulate was injection molded by using an Engel ES 200/50HL machine.
  • the zone temperafares and mold temperafare of the injector were set according to the following list:
  • thermotropic in-sifa LC fibers retained their solid state and oriented according to the flow field which prevailed during the injection molding. From the dilution, test bars were melt molded which complied with the standard ISO 3167. The following physical properties were measured from the pieces, the corresponding values for the matrix material PP VB65 50B (Neste Oy Chemicals) are given in parentheses: - tensile elasticity modulus/
  • Example 3 Preparation and injection molding of a compatibilized polypropylene/liquid crystal polymer dilution
  • the prepared concentrate was diluted with the matrix polymer of Example 1, PP VB65 50B (Neste Oy Chemicals), and at the same time a commercial compatibilizer, Lotader AX 8660 (Norsolor) was added to it. It is a terpolymer of ethylene, acrylic ester and glycidyl metacrylate.
  • the mixfare contained concentrate 58 % by weight, compatibilizer 2 % by weight, and diluting polymer 40 % by weight; thus the final proportion of liquid crystal polymer Vectra R A950 was 32 % by weight.
  • the diluted and compatibilized mixture was compounded in a twin-screw extruder, Berstorff ZE 25 x 33 D, and the screw geometry selected was the device manufacfarer's "Polyblends 1" configuration.
  • the zone temperafares were adjusted as follows: 50-220- 220-220-230-230-230-230 °C.
  • the granulate was injection molded by using an Engel ES 200/50HL machine.
  • thermotropic in-sifa LC fibers retained their solid state and oriented according to the flow field which prevailed during the injection molding. From the compatibilized dilution, test bars were melt molded which were in compliance with the standard ISO 3167. The following physical properties were measured from the bars; the corresponding values for the matrix material, PP VB65 50B (Neste Oy Chemicals) are given in parentheses:
  • Example 4 Preparation and injection molding of a polypropylene/liquid crystal polymer dilution containing a compound which improves processability
  • the prepared concentrate was diluted by using the matrix polymer of Example 1, PP VB65 50B (Neste Oy Chemicals); at the same time a commercial liquid crystal polymer, Rodrun LC-3000 (Unitika Ltd.), melting at a lower temperafare than the reinforcement material Vectra R A950, was added to it.
  • the mixfare contained concentrate 40 % by weight, processability-improving liquid crystal polymer 10 % by weight, and diluting polymer 50 % by weight.
  • the final proportion of the LC resin Vectra R A950 serving as the reinforcement was 32 % by weight.
  • the diluted mixfare containing a liquid crystal polymer which improves processability was compounded in a twin-screw extruder, Berstorff ZE 25 x 33 D, and the screw geometry selected was the device manufacfarer's "Polyblends 1" configuration.
  • the zone temperatu ⁇ res were selected as follows: 50-220-220-220-230-230-230-230 °C.
  • the granulate was injection molded by using an Engel ES 200/50HL machine.
  • the zone temperafares and mold temperature of the injector were set according to the list below:
  • thermotropic in-sifa LC fibers retained their solid state and oriented according to the flow field which prevailed dining the injection molding.
  • test bars were melt molded which were in compliance with the standard ISO 3167. The following physical properties were measured from the bars; the corresponding values for the matrix material, PP VB65 50B (Neste Oy Chemicals) are given in parentheses:
  • ISO-R527 3.1 GPa (1.4 GPa) - tensile yield strength/
  • Example 5 Preparation and injection molding of a polypropylene/liquid crystal polymer by using a polyamide/polypropylene mixfare
  • the prepared concentrate was diluted with a polyamide/polypropylene mixfare.
  • the formed composite material contained concentrate 40 % by weight and diluting mixfare 60 % by weight; thus the final proportion of the liquid crystal polymer, Vectra R A950, was 32 % by weight.
  • the diluted mixture was compounded in a twin-screw extruder, Berstorff ZE 25 x 33 D, and the screw geometry selected was the device manufacfarer's "Polyblends 1" configura ⁇ tion.
  • the zone temperatures were set as follows: 50-230-230-230-230-230-230 °C.
  • the granulate was injection molded by using an Engel ES 200/50HL machine.
  • the zone temperatures and mold temperafare of the injector were set according to the list below:
  • thermotropic in-sifa LC fibers retained their solid state and oriented according to the flow field which prevailed during the injection molding. From the dilution containing the resin mixture, test bars were melt molded which were in compliance with the standard ISO 3167. The following physical properties were measured from the bars; the corresponding values for the matrix material, PP VB65 50B (Neste Oy Chemicals) are given in parentheses:
  • ISO-R527 2.5 GPa (1.4 GPa) - tensile yield strength/
  • Example 6 Preparation and injection molding of a polypropylene/liquid crystal polymer dilution by using a thermoplastic elastomer
  • the prepared concentrate was diluted with a commercial thermoplastic elastomer, Santoprene 201-80 (Monsanto PLC).
  • the mixfare contained concentrate 40 % by weight and elastomer 60 % by weight; thus the final proportion of the liquid crystal polymer, Vectra R A950, was 32 % by weight.
  • the diluted mixfare was compounded in a twin-screw extruder, Berstorff ZE 25 x 33 D, and the screw geometry selected was the device manufacturer's "Polyblends 1" configura ⁇ tion.
  • the zone temperatures were set as follows: 50-190-190-190-200-200-200-200- 200 °C.
  • the granulate was injection molded by using an Engel ES 200/50HL machine.
  • the zone temperatures and mold temperafare of the injector were set according to the list below:
  • thermotropic in-sifa LC fibers retained their solid state and oriented according to the flow field which prevailed during the injection molding.
  • test bars were melt molded which were in compliance with the standard ISO 3167. The following physical properties were measured from the bars; the corresponding values for the matrix material, PP VB65 50B (Neste Oy Chemicals) are given in parentheses:

Landscapes

  • 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)
  • Injection Moulding Of Plastics Or The Like (AREA)

Abstract

A two-step process for the preparation of a mixture which contains in situ liquid crystal polymer fibers and one or more matrix polymers, wherein, in the first step, a mixture of a liquid crystal polymer and a matrix polymer is prepared which contains liquid crystal polymer 60-95 % (concentrate), by compounding the polymer mixture at so high a temperature that the liquid crystal resin will melt, and in the second step, the obtained mixture is diluted with the matrix resin so that the final mixture will contain liquid crystal resin 5-60 %, by compounding the mixture at a temperature at which the liquid crystal resin will not melt but the matrix resin will.

Description

A P.ETHOD FOR PREPARING POLYMER BLENDS WHICH CONTAIN IN-SITU LIQUID CRYSTAL POLYMER FIBERS.
The invention relates to a two-step process for the preparation of a mixture of a liquid crystal polymer and a matrix polymer.
Liquid crystal polymers (LCP) are polymers which, when molten, are intermediate forms of a solid-state substance and a liquid. The liquid crystal phase is indeed called a 'meso- morphic phase' or an ' amsotropic phase', since liquid crystal polymers are macroscopical- ly fluid when molten. Microscopically they have a regular structure, as have crystals.
Liquid crystal polymers are made up of stiff linear or spiral molecule chains. Their principal components are aromatic cyclic structures, which are usually interlinked by ester, ether or amide bonds. Liquid crystal polymers spontaneously arranging in molten state are called thermotropic and those arranging in liquid state are called lyotropic. The more linear and the more tactic the molecules of liquid crystal polymers, the more com¬ pletely and the more rapidly they will crystallize. Liquid crystal resins are usually typical semicrystalline polymers, but their molecules solidified into a glass state are not oriented randomly but monoaxially, i.e. nematically.
Thermotropic liquid crystal resins constitute a very wide polymer group, in which the properties of the various types differ significantly from each other. On the basis of their heat deflection temperature, liquid crystal polymers can be divided into three categories.
The liquid crystal polymers belonging to the first category crystallize almost completely, and so their heat resistance is very high. Commercial Xydar (Amoco Premark), consisting of p,p'-biphenol, p-hydroxybenzoic acid and terephthalic acid, belongs to this category. The strength and stiffness of LC polymers of the first category are high owing to rectilinear molecule chains. These thermotropic polymers can be processed by conven¬ tional melt-molding methods for resins, for example by injection molding.
Owing to its liquid crystal behavior, Xydar has a viscosity of approx. 1000 Pa s, the measuring temperature being 430 °C and the measuring shear rate being 1000 s"1. Since the LC transition, analogous to melting, of the thermotropic polymers of the first category takes place at a very high temperature (Xydar SRT-300, 421 °C), they must be processed by using modified extruders and injectors.
The thermotropic liquid crystal polymers of the second category are synthesized from monomers the conformations of which inhibit dense packing of the molecule chains and at the same time their excessive crystallization, and thus their LC transition temperature drops. These thermotropic polymers are typical semicrystalline thermoplastic resins, but their molecules, solidified into an amorphous glass state, are not oriented randomly but monoaxially, i.e. nematically. The heat resistance of the thermotropic polymers of the second category is not determined according to the LC glass transition temperature, because the heat deflection temperature of those liquid crystal polymers is in general closer to the temperature of liquid crystal transition than that of glass transition. The best known commercial polymer is Vectra A900 (Hoechst Celanese) synthesized from p-hydr- oxybenzoic and 6-hydroxy-2-naphthoic acids, having an LC transition point of 280 °C, a heat deflection temperature of 180 °C (1.82 MPa), and a typical degree of crystallinity of 20 %. The viscosity of the said liquid crystal copolyester at a temperature of 300 °C and at a shear rate of lOOO"1 is 60 Pa s.
The processability of the thermotropic polymers of the third category has been improved by adding to a stiff molecule a flexible unit, for example a methylene chain, whereby their crystallinity and heat deflection temperature drop but their tenacity increases. An example of commercial polymers of this type is X7-G (Eastman Kodak), synthesized from p- acetoxybenzoic acid and polyethylene terephthalate. Its viscosity is approx. 10 Pa s, the temperature being 260 °C and the shear rate 1000 s"1.
Conventional polymers, among others polyethylene and polypropylene, are made up of flexible molecule chains which are grouped either randomly or in an ordered manner. Within the amorphous range the molecule chains are located completely at random, whereas within the ordered range the polymers are crystallized as three-dimensional structures. Amorphous polymers are isotropic both at the macro level and at the micro level. Thermoplastics are usually semicrystalline polymers. Semicrystalline and crystalline (100 %) conventional thermoplastics are microscopically amsotropic but macroscopically isotropic.
Certain properties of stiff anisotropic liquid crystal polymers are superior to those of conventional isotropic resins. They have a lower viscosity, better mechanical properties, a lower linear coefficient of thermal expansion (CTE), as well as better resistance to heat and chemicals.
However, also detrimental properties follow from the anisotropic character of liquid crystal polymers. Their longitudinal mechanical properties are multiple as compared with the transverse ones, and their surface layers fibrillate easily.
Since liquid crystal polymers are made up of stiff linear molecules, at the macro level they are comparable to carbon fibers or glass fibers. When liquid crystal polymers are mixed with conventional isotropic polymers, their stiff molecules will reinforce the matrix material in the same manner as do carbon fibers or glass fibers. Liquid crystal polymers and conventional matrix resins are in general not miscible with each other at the molecular level; they form a two-phase system. At rest a liquid crystal polymer is dispersed as spherical blocks in an isotropic matrix. When this polymer mixture is subjected to a shearing and/or stretching flow, the block-like liquid crystal areas stretch in the field of shearing or stretching stress, since the stiff LC molecules easily slide one past another. Depending on the field of deformation, the liquid crystalline areas turn into in-situ fibers or sheets. In order for the relative movement of the LC polymer and the matrix resin to be possible, the components must not mix with each other, and they must not be comple¬ tely compatible. Furthermore, the viscosity of the liquid crystal polymer must be lower than that of the isotropic matrix.
The present invention relates to mixtures of a liquid crystal polymer and a matrix resin, prepared in two steps. In the first step, a liquid crystal polymer dominant concentrate is prepared in which the matrix polymer consists of one of more conventional polymers (e.g. polypropylene). The proportion of liquid crystal polymer in the concentrate is at minimum 60 %. In connection with melt molding the liquid crystal polymer is melted, whereupon it will fiberize in the processing device itself, such as a compounder (in situ). The formed concentrate bar is cut into the desired length, whereafter it is fed into a second extruder. The temperature of this device is set at a level below the melting point of the liquid crystal polymer, and so the LC fibers formed in the first compounding step will not melt. At the same time, additives such as viscosity reducers, bonding agents, and compatibili- zers may be fed into the extruder. The completed product is granulated, which enables further processing to be carried out, for example, by injection molding. When flexible situ liquid crystal fibers arrive in a stretching and shearing flow field in the screw and mold of the processing machine, they become deformed, only the microstructure beco¬ ming fibrillated. Thus the unmelted liquid crystal polymer fibers will not break in the way stiff glass or carbon fibers do. The length of the granulated liquid crystal fibers will remain unchanged, but their flexibility will increase owing to fibrillation, and therefore they will twist into a tangle as the melt flows in the flow conduits and the mold cavity. A piece thus injection molded will be more isotropic than pieces made using stiff and brittle reinforcements.
Usually resin mixtures which contain liquid crystal polymers are processed, for example, in a twin-screw extruder at so high a temperature that also the liquid crystal polymer will melt, in which case the reinforcing occurs at the molecular level. In the present invention, only a concentrate which contains a liquid crystal polymer is prepared by the said method.
A two-step preparation of a mixture of a liquid crystal polymer and a matrix polymer is also described in EP application publication 499387. According to it, also, first a 'concentrate' is made which contains more than 2 % liquid crystal polymer, and in the second step the mixture is diluted to the degree that the content of liquid crystal polymer will be less than 2 % . However, the melt-mixing temperatures in both steps are such that the liquid crystal polymer will not melt, i.e. the process does not aim at forming in-sifa fibers.
According to the present invention, the LCP content in the concentrate is more than 60 % by weight, preferably 70-90 % by weight. The matrix polymer may be any conventional polymer (e.g. polyethylene, polypropylene), engineering polymer (e.g. polyamide, polyethylene terephthalate), elastomer (e.g. EPDM and SEBS), or a lower-melting aromatic polymer (e.g. HB A/PET). The chemical structure of the matrix resin is not limited to homopolymers; also copolymers, which may be block-structured, random structured or branched, are possible. The molar mass distributions and the polymer modality are selected according to the targeted application. Of course, mixtures of two or more polymers may also be used. A liquid crystal polymer of the first, second or third category, or various mixtures thereof, may be used as the reinforcement.
In the second step of the invention, the concentrate containing a liquid crystal polymer is diluted either with the same matrix resin as in the first compounding, or with a different one. The zone temperatures in the processing machine, such as a single- or twin-screw extruder, must be set so that the temperature of the molten compound will not exceed the melting point of the liquid crystal polymer fiberized in the preceding step. Thus the retaining of the in-situ LC fibers is ensured, which is the key point of the invention. The diluted mixture containing a liquid crystal polymer is run through the nozzle of the processing machine. Thereafter the formed extrusion profile is cooled and granulated, according to the intended use, into either short or long pellets. The content of liquid crystal polymer can be diluted to 5-60 % by weight.
Additives may also be added during the diluting step to the mixture containing a liquid crystal polymer. By means of the additives it is possible, for example, to improve adhesion between the LC reinforcement and the matrix resin, mainly with respect to the solid liquid crystal fibers. It is also possible to enhance the interactions between com¬ ponents of an immiscible and incompatible polymer mixture by means of compatibilizers. Compatibilizing may be based on functionalized doping components, polymeric compatibi¬ lizers, or small-molecular compatibilizing compounds. Compatibilizing may be carried out during the diluting step, but often preferably already in connection with the preparation of the concentrate. In the diluting step it is also possible to improve the flow properties of the doped compound by using agents which reduce the viscosity of the polymer system, such as small-molecular chemicals or a second crystal polymer, which melts at a lower temperature. Mineral fillers (e.g. chalk and talcum), organic compounds (e.g. carbon fiber and carbon black or PET staple) or inorganic materials (e.g. glass fiber and silica derivatives in whisker form) can, of course, be added to the dilution of the concentrate, depending the property requirements of the final application.
The diluted concentrate containing a liquid crystal polymer, according to the invention, is processed to its final form according to the intended application, for example, by injection molding, pipe extrusion, blow molding or thermoforming. In this step, as in connection with the diluting, the zone temperatures of the processing machine (e.g. an injector) must be set in such a manner that the temperature of the molten compound will not exceed the melting point of the fiberized liquid crystal polymer. This ensures that the in-sifa LC fibers are retained all the way to the end product. Since in-situ liquid crystal fibers are fibrillized in a shearing and stretching field, they become more flexible. Therefore they are more isotropically oriented by the deformation differences appearing in the flow of the compound; this is also reflected in the properties of the end product/piece. By using i ; sifa LC fibers according to the invention, a matrix material can be reinforced more effectively than by using, for example, stiff carbon or glass staple fibers, since, owing to fibrillation, the flexibility of the liquid crystalline fibers is increased. Owing to the said mechanism, the length of the LC fibers will remain unchanged in the processing step, usually at a value higher than the critical value, contrary to that of carbon or glass fibers, which become ground into shorter units in flow fields.
The process of the invention provides, over in-sifa LC fibers formed in one processing step, the advantage that the diameter and length of the fiber can be adjusted so as to be better suited for the end application. Since in the first step of the invention the material is a concentrate in which the dominating component is a liquid crystal polymer, it will become better fiberized and better oriented under shearing and stretching deformation than will a final compound containing a larger amount of a conventional isotropic resin. Since in the second step the in-sifa LC fibers already formed are no longer melted, their length will not change. This leads to a reinforcement which is more isotropic than could be achieved by using an LC melt only. Furthermore, the interface between the solid liquid crystal fibers and the matrix plastic is well-defined, which enables bonding agents to be used more effectively, since they can be linked by chemical bonds to the forming in-sifa LC fibers already in the first reactive molding step. The necessary additives, e.g. bonding agents, compatibilizers and stabilizers, are fed into the process in either the first or the second step of the invention, depending on the reactive components and reaction kinetics used. By the process described in the invention it is possible to improve the properties, such as ductility, of mixtures of isotropic resins and thermotropic liquid crystal polymers prepared in one step. The invention is described below with the help of the following embodiment examples.
Example 1. Preparation of a concentrate containing a liquid crystal polymer
Homopolypropylene VB65 50B (Neste Oy Chemicals) was selected as the matrix material and VectraR A950 (Hoechst Celanese), which is a copolymer of p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid, as the liquid crystal polymer. The melting point of the polypropylene used is 164 °C and that of the fully aromatic copolyester is 280 °C. The said components were mixed in the form of granulates, whereafter the mixture was dried for 10 hours at 80 °C. In the concentrate the proportion of liquid crystal polymer was 80 % by weight and that of polypropylene 20 % by weight.
The dried component mixture was compounded in a twin-screw extruder, Berstorff ZE 25 x 33 D, and the screw geometry selected was the device manufacturer's "Polyblends 1 " configuration. The zone temperafares were set as follows: 50-285-285-285-290-290-290- 290 °C.
300 °C was measured as the compound temperature, and the rotation speed of the screw was set at 200 rpm. The liquid crystal polymer was fiberized in the shearing and stret- ching field (in situ) of the nozzle of the twin-screw extruder. The concentrate bar was cut into granules 10 mm long.
Example 2. Dilution and injection molding of a polypropylene/liquid crystal polymer mixture
The prepared concentrate was diluted with the matrix polymer of Example 1, PP VB65 50B (Neste Oy Chemicals). The mixture contained concentrate 40 % by weight and diluting polymer 60 % by weight, and thus the final proportion of polypropylene was 68 % by weight and the proportion of liquid crystal polymer VectraR A950 was 32 % by weight.
The diluted mixture was compounded in a twin-screw extruder, Berstorff ZE 25 x 33 D, and the screw geometry selected was the device manufacturer's "Polyblends 1" configura- tion. The zone temperatures were set as follows: 50-200-200-200-200-200-200-200 °C.
220 °C was measured as the compound temperature, and the rotation speed of the screw was set at 200 rpm. The bar obtained from the extruder was cut into granules 3 mm long.
The granulate was injection molded by using an Engel ES 200/50HL machine. The zone temperafares and mold temperafare of the injector were set according to the following list:
Figure imgf000010_0001
-T2 = 195 °C (zone 2) -T3 = 200 °C (zone 3)
-T4 = 200 °C (zone 4)
-Tn = 200 °C (nozzle)
-Tm = 40 °C (mold)
203 °C was measured as the temperafare of the molten compound. The other process parameters used in the injection molding were as follows:
- injection rate = 90 mm/s
- injection pressure = 55 bar (measured)
- afterpressure profile = 60-55-50-45-40-35-25-20-10 bar - afterpressure time = 25 s
- cooling time = 10 s
- counter-pressure = 2.5 bar rotation speed of screw = 190 rpm
Since the temperafare of the diluted concentrate in molten state did not exceed the melting point of the liquid crystal polymer VectraR A950 used, the thermotropic in-sifa LC fibers retained their solid state and oriented according to the flow field which prevailed during the injection molding. From the dilution, test bars were melt molded which complied with the standard ISO 3167. The following physical properties were measured from the pieces, the corresponding values for the matrix material PP VB65 50B (Neste Oy Chemicals) are given in parentheses: - tensile elasticity modulus/
ISO-R527 = 2.4 GPa (1.4 GPa)
- tensile yield strength/
ISO-R527 = 27 MPa (35 MPa) - elongation at yield/ISO-R527 = 4.5 % (10 %)
- flexural modulus/ISO 178 = 2.5 GPa (1.6 GPa)
- notched Charpy impact strength
(23°C)/ISO 179-1 A = 2.3 kJ/m2 (4.0 kJ/m2)
- heat deflection temperafare (HDT/B)/ISO 75 = 140 °C (93 °C)
The results show that the in-situ LC fibers improve the properties of the matrix polymer.
Example 3. Preparation and injection molding of a compatibilized polypropylene/liquid crystal polymer dilution
The prepared concentrate was diluted with the matrix polymer of Example 1, PP VB65 50B (Neste Oy Chemicals), and at the same time a commercial compatibilizer, Lotader AX 8660 (Norsolor) was added to it. It is a terpolymer of ethylene, acrylic ester and glycidyl metacrylate. The mixfare contained concentrate 58 % by weight, compatibilizer 2 % by weight, and diluting polymer 40 % by weight; thus the final proportion of liquid crystal polymer VectraR A950 was 32 % by weight.
The diluted and compatibilized mixture was compounded in a twin-screw extruder, Berstorff ZE 25 x 33 D, and the screw geometry selected was the device manufacfarer's "Polyblends 1" configuration. The zone temperafares were adjusted as follows: 50-220- 220-220-230-230-230-230 °C.
245 °C was measured as the compound temperature, and the rotation speed of the screw was set at 200 rpm. The bar obtained from the extruder was cut into granules 3 mm long.
The granulate was injection molded by using an Engel ES 200/50HL machine. The zone
9 temperatures and mold temperature of the injector were set according to the list below: -Tt = 190 °C (zone 1)
-T2 = 195 °C (zone 2)
-T3 = 200 °C (zone 3)
-T4 = 200 °C (zone 4) -Tn = 200 °C (nozzle)
-Tm = 40 °C (mold)
204 °C was measured as the temperature of the molten compound. The other process parameters used in the injection molding were as follows: - injection rate = 90 mm/s
- injection pressure = 55 bar (measured)
- afterpressure profile = 60-55-50-45-40-35-25-20-10 bar
- afterpressure time = 25 s
- cooling time = 10 s - counter-pressure = 2.5 bar
- rotation speed of the screw = 190 rpm
Since the temperafare of the diluted concentrate in molten state did not exceed the melting point of the liquid crystal polymer used, VectraR A950, the thermotropic in-sifa LC fibers retained their solid state and oriented according to the flow field which prevailed during the injection molding. From the compatibilized dilution, test bars were melt molded which were in compliance with the standard ISO 3167. The following physical properties were measured from the bars; the corresponding values for the matrix material, PP VB65 50B (Neste Oy Chemicals) are given in parentheses:
- tensile elasticity modulus/
ISO-R527 = 1.8 GPa (1.4 GPa)
- tensile yield strength/ ISO-R527 = 25 MPa (35 MPa)
- elongation at yield/ISO-R527 = 4.5 % (10 %)
- flexural modulus/ISO 178 = 2.2 GPa (1.6 GPa)
- notched Charpy impact strength
(23°C)/ISO 179-1 A = 2.4 kJ/m2 (4.0 kJ/m2) heat deflection temperafare
(HDT/B)/ISO 75 = 99 °C (93 °C)
The results show that the in-sifa LC fibers improve the properties of the matrix polymer, but are somewhat poorer than in Example 2.
Example 4. Preparation and injection molding of a polypropylene/liquid crystal polymer dilution containing a compound which improves processability
The prepared concentrate was diluted by using the matrix polymer of Example 1, PP VB65 50B (Neste Oy Chemicals); at the same time a commercial liquid crystal polymer, Rodrun LC-3000 (Unitika Ltd.), melting at a lower temperafare than the reinforcement material VectraR A950, was added to it. The mixfare contained concentrate 40 % by weight, processability-improving liquid crystal polymer 10 % by weight, and diluting polymer 50 % by weight. Thus the final proportion of the LC resin VectraR A950 serving as the reinforcement was 32 % by weight.
The diluted mixfare containing a liquid crystal polymer which improves processability was compounded in a twin-screw extruder, Berstorff ZE 25 x 33 D, and the screw geometry selected was the device manufacfarer's "Polyblends 1" configuration. The zone temperatu¬ res were selected as follows: 50-220-220-220-230-230-230-230 °C.
243 °C was measured as the temperafare of the compound, and the rotation speed of the screw was set at 200 rpm. The bar obtained from the extruder was cut into granules 3 mm long.
The granulate was injection molded by using an Engel ES 200/50HL machine. The zone temperafares and mold temperature of the injector were set according to the list below:
-T, = 220 °C (zone 1)
-τ2 = 225 °C (zone 2)
-τ3 = 230 °C (zone 3)
-τ4 = 230 °C (zone 4)
-τn = 235 °C (nozzle) -Tm = 40 °C (mold)
235 °C was measured as the temperature of the molten compound. The other process parameters used in the injection molding were as follows: - injection rate = 90 mm/s
- injection pressure = 36 bar (measured)
- afterpressure profile = 60-55-50-45-40-35-25-20-10 bar
- afterpressure time = 25 s
- cooling time = 10 s - counter-pressure = 2.5 bar
- rotation speed of the screw = 190 rpm
Since the temperature of the diluted concentrate in molten state did not exceed the melting point of the liquid crystal polymer used, VectraR A950, the thermotropic in-sifa LC fibers retained their solid state and oriented according to the flow field which prevailed dining the injection molding. From the dilution containing a liquid crystal polymer which improves processability, test bars were melt molded which were in compliance with the standard ISO 3167. The following physical properties were measured from the bars; the corresponding values for the matrix material, PP VB65 50B (Neste Oy Chemicals) are given in parentheses:
- tensile elasticity modulus/
ISO-R527 = 3.1 GPa (1.4 GPa) - tensile yield strength/
ISO-R527 = 30 MPa (35 MPa)
- elongation at yield/ISO-R527 = 1.9 % (10 %)
- flexural modulus/ISO 178 = 3.3 GPa (1.6 GPa)
- notched Charpy impact strength (23°C)/ISO 179-1 A = 2.3 kJ/m2 (4.0 kJ/m2)
- heat deflection temperafare
(HDT/B)/ISO 75 = 134 °C (93 °C)
The results show that the in-sifa LC fibers together with another, lower-melting liquid crystal polymer improve the properties of the matrix polymer.
Example 5. Preparation and injection molding of a polypropylene/liquid crystal polymer by using a polyamide/polypropylene mixfare
The prepared concentrate was diluted with a polyamide/polypropylene mixfare. The formed composite material contained concentrate 40 % by weight and diluting mixfare 60 % by weight; thus the final proportion of the liquid crystal polymer, VectraR A950, was 32 % by weight.
The diluted mixture was compounded in a twin-screw extruder, Berstorff ZE 25 x 33 D, and the screw geometry selected was the device manufacfarer's "Polyblends 1" configura¬ tion. The zone temperatures were set as follows: 50-230-230-230-230-230-230-230 °C.
247 °C was measured as the compound temperature, and the rotation speed of the screw was set at 200 rpm. The bar obtained from the extruder was cut into granules 3 mm long.
The granulate was injection molded by using an Engel ES 200/50HL machine. The zone temperatures and mold temperafare of the injector were set according to the list below:
Figure imgf000015_0001
-τ2 = 225 °C (zone 2)
-τ3 = 230 °C (zone 3)
-τ4 = 230 °C (zone 4)
-τ„ = 230 °C (nozzle)
-τm = 40 °C (mold)
232 °C was measured as the temperature of the molten compound. The other process parameters used in the injection molding were as follows:
- injection rate = 90 mm/s - injection pressure = 55 bar (measured)
- afterpressure profile = 60-55-50-45-40-35-25-20-10 bar
- afterpressure time = 25 s
- cooling time = 10 s - counter-pressure = 2.5 bar
- rotation speed of the screw = 190 rpm
Since the temperature of the diluted concentrate in molten state did not exceed the melting point of the liquid crystal polymer used, VectraR A950, the thermotropic in-sifa LC fibers retained their solid state and oriented according to the flow field which prevailed during the injection molding. From the dilution containing the resin mixture, test bars were melt molded which were in compliance with the standard ISO 3167. The following physical properties were measured from the bars; the corresponding values for the matrix material, PP VB65 50B (Neste Oy Chemicals) are given in parentheses:
- tensile elasticity modulus/
ISO-R527 = 2.5 GPa (1.4 GPa) - tensile yield strength/
ISO-R527 = 28 MPa (35 MPa)
- elongation at yield/ISO-R527 = 3.4 % (10 %)
- flexural modulus/ISO 178 = 2.5 GPa (1.6 GPa)
- notched Charpy impact strength (23°C)/ISO 179-1 A = 1.5 kJ/m2 (4.0 kJ/m2)
- heat deflection temperature
(HDT/B)/ISO 75 = 137 °C (93 °C)
The results show that the in-sifa LC fibers improve the properties of the matrix polymer in a manner corresponding to that in Example 2.
Example 6. Preparation and injection molding of a polypropylene/liquid crystal polymer dilution by using a thermoplastic elastomer
The prepared concentrate was diluted with a commercial thermoplastic elastomer, Santoprene 201-80 (Monsanto PLC). The mixfare contained concentrate 40 % by weight and elastomer 60 % by weight; thus the final proportion of the liquid crystal polymer, VectraR A950, was 32 % by weight. The diluted mixfare was compounded in a twin-screw extruder, Berstorff ZE 25 x 33 D, and the screw geometry selected was the device manufacturer's "Polyblends 1" configura¬ tion. The zone temperatures were set as follows: 50-190-190-190-200-200-200-200- 200 °C.
219 °C was measured as the compound temperature, and the rotation speed of the screw was set at 200 rpm. The bar obtained from the extruder was cut into granules 3 mm long.
The granulate was injection molded by using an Engel ES 200/50HL machine. The zone temperatures and mold temperafare of the injector were set according to the list below:
Figure imgf000017_0001
-T2 = 195 °C (zone 2)
-T3 = 200 °C (zone 3)
-T4 = 200 °C (zone 4) -Tn = 200 °C (nozzle)
-Tm = 40 °C (mold)
203 °C was measured as the temperafare of the molten compound. The other process parameters used in the injection molding were as follows: - injection rate = 90 mm s
- injection pressure = 45 bar (measured)
- afterpressure profile = 60-55-50-45-40-35-25-20-10 bar
- afterpressure time = 25 s
- cooling time = 10 s - counter-pressure = 2.5 bar
- rotation speed of the screw = 190 rpm
Since the temperature of the diluted concentrate in molten state did not exceed the melting point of the liquid crystal polymer used, VectraR A950, the thermotropic in-sifa LC fibers retained their solid state and oriented according to the flow field which prevailed during the injection molding. From the dilution containing a thermoplastic elastomer, test bars were melt molded which were in compliance with the standard ISO 3167. The following physical properties were measured from the bars; the corresponding values for the matrix material, PP VB65 50B (Neste Oy Chemicals) are given in parentheses:
- tensile elasticity modulus/ ISO-R527 = 0.5 GPa (1.4 GPa)
- tensile yield strength/
ISO-R527 = 5.6 MPa (35 MPa)
- elongation at yield/ISO-R527 = 112 % (10 %)
- flexural modulus/ISO 178 = 0.6 GPa (1.6 GPa) - notched Charpy impact strength
(23°C)/ISO 179-1A = 33.3 kJ/m2 (4.0 kJ/m2)
- heat deflection temperafare
(HDT/B)/ISO 75 = 74 °C (93 °C)
The results show that the in-sifa LC fibers improve the elastic properties of the matrix polymer but decrease its strength, stiffness and heat deflection temperafare.

Claims

Claims:
1. A two-step process for the preparation of a mixfare which contains in-sifa liquid crystal polymer fibers and one or more matrix polymers, characterized in that in the first step a mixture of a liquid crystal polymer and a matrix polymer is prepared which contains liquid crystal polymer 60-95 % (concentrate), by compounding the polymer mixfare at so high a temperafare that the liquid crystal resin will melt, and in the second step the obtained compound is diluted with the matrix resin so that the final mixfare will contain liquid crystal resin 5-60 %, by compounding the mixfare at a temperafare at which the liquid crystal resin will not melt but the matrix resin will.
2. A process according to Claim 1, characterized in that the in-sifa liquid crystal polymer fibers are produced in connection with the preparation of the concentrate.
3. A process according to Claim 1 , characterized in that the mixture prepared in the first step contains liquid crystal polymer 70-90 % .
4. A process according to Claim 1, characterized in that the diluted polymer mixfare contains liquid crystal polymer 25-40 %.
5. A process according to Claim 1, characterized in that in the first step or the second step a compatibilizer is added to improve the compatibility of the polymers.
6. A process according to Claim 1, characterized in that, in connection with the diluting, processing agents, coupling agents, lubricants or other additives are added to the polymer mixfare.
7. A process according to Claim 1, characterized in that the processing agent added in connection with the diluting is a second liquid crystal polymer.
8. A process according to Claim 1, characterized in that the diluting is carried out using the same matrix resin as was used for the preparation of the concentrate.
9. A process according to Claim 1, characterized in that the diluting is carried out using a matrix resin different from that used for the preparation of the concentrate.
10. A process according to Claim 1, characterized in that the matrix resin used for the preparation of the concentrate is polypropylene.
11. A mixture of a liquid crystal polymer and a matrix polymer, containing in-sifa fibers, prepared by the process according to Claim 1.
12. Products made from the mixfare according to Claim 11.
PCT/FI1994/000345 1993-08-10 1994-08-09 A method for preparing polymer blends which contain in situ liquid crystal polymer fibers WO1995004782A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI933516A FI933516A (en) 1993-08-10 1993-08-10 In-situ method of preparing a polymer blend containing a liquid crystal polymer fiber
FI933516 1993-08-10

Publications (1)

Publication Number Publication Date
WO1995004782A1 true WO1995004782A1 (en) 1995-02-16

Family

ID=8538396

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/FI1994/000345 WO1995004782A1 (en) 1993-08-10 1994-08-09 A method for preparing polymer blends which contain in situ liquid crystal polymer fibers

Country Status (2)

Country Link
FI (1) FI933516A (en)
WO (1) WO1995004782A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1086987A1 (en) * 1999-09-27 2001-03-28 DuPont-Mitsui Fluorochemicals Co., Ltd. Method of fabricating composite fluoroplastic articles
US6660182B2 (en) 2000-09-01 2003-12-09 Ticona Llc Blends of stretchable liquid crystal polymers with thermoplastics

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0499387A2 (en) * 1991-02-13 1992-08-19 Bp America Inc. Polymer composites of thermoplastic and liquid crystal polymers and a process for their preparation
WO1992019676A1 (en) * 1991-05-01 1992-11-12 Virginia Polytechnic Institute And State University Mixing process for generating in-situ reinforced thermoplastics
DE4232822A1 (en) * 1991-09-30 1993-04-08 Mazda Motor Liq. crystal-resin composites with low resin content - by mixing resin with thermoplastic matrix resin, melt-extruding to raw composite, adding more matrix resin and injection moulding the mixt.
EP0552742A1 (en) * 1992-01-20 1993-07-28 Mazda Motor Corporation Method for injection molding of liquid crystal resin composite and molded article

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0499387A2 (en) * 1991-02-13 1992-08-19 Bp America Inc. Polymer composites of thermoplastic and liquid crystal polymers and a process for their preparation
WO1992019676A1 (en) * 1991-05-01 1992-11-12 Virginia Polytechnic Institute And State University Mixing process for generating in-situ reinforced thermoplastics
DE4232822A1 (en) * 1991-09-30 1993-04-08 Mazda Motor Liq. crystal-resin composites with low resin content - by mixing resin with thermoplastic matrix resin, melt-extruding to raw composite, adding more matrix resin and injection moulding the mixt.
EP0552742A1 (en) * 1992-01-20 1993-07-28 Mazda Motor Corporation Method for injection molding of liquid crystal resin composite and molded article

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
STN INTERNATIONAL, File CA, Chemical Abstracts, Volume 119, No. 14, 4 October 1993 (Columbus, Ohio, US), CREVECOEUR G. et al., "Fibril Formation in In Situ Composites of a Thermotropic Liquid-crystalline Polymer in a Thermoplastic Matrix", Abstract No. 140273; & J. APPL. POLYM. SCI., (1993), 49(5), *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1086987A1 (en) * 1999-09-27 2001-03-28 DuPont-Mitsui Fluorochemicals Co., Ltd. Method of fabricating composite fluoroplastic articles
US6660182B2 (en) 2000-09-01 2003-12-09 Ticona Llc Blends of stretchable liquid crystal polymers with thermoplastics

Also Published As

Publication number Publication date
FI933516A0 (en) 1993-08-10
FI933516A (en) 1995-02-11

Similar Documents

Publication Publication Date Title
US4728698A (en) Liquid crystal fiber-reinforced polymer composite and process for preparing same
EP0790280B1 (en) Thermoplastic resin composition, injection molding method thereof and injection molded article
JP2862303B2 (en) Polymer blend molding method
Evstatiev et al. Structure‐property relationships of injection‐and compression‐molded microfibrillar‐reinforced PET/PA‐6 composites
US6221962B1 (en) Liquid crystal polymer blends, process for the preparation thereof and products manufactured from the blends
BR112017000872B1 (en) COMPATIBILIZED THERMOPLASTIC PELLETIZABLE POLYMER ALLOY COMPOSITION
US20090283202A1 (en) Process for the welding of two polyamide parts
CA2123080A1 (en) Process for making polyamide/polyolefin blends having superior improved toughness and stiffness
KR20160055953A (en) Composition comprising polyamide 66 and a polyamide chosen from the group consisting of: polyamide 610, polyamide 1010 and polyamide 1012
JP3584890B2 (en) Thermoplastic resin molded article and method for producing the same
WO2004024821A1 (en) Moulding composition comprising nylon-6 and a fibrous reinforcing agent
WO1995004782A1 (en) A method for preparing polymer blends which contain in situ liquid crystal polymer fibers
JP2008201863A (en) Method for producing molded article of polylactic acid resin
KR960007471B1 (en) Method for molding liquid crystal resin composite
JP3415346B2 (en) Injection molding method
JP3170555B2 (en) Injection molding
JPH0737577B2 (en) Self-reinforcing polymer composite and method for producing the same
JP3355061B2 (en) Thermoplastic resin composition, injection molding method and injection molded article thereof
JP3186858B2 (en) Liquid crystal resin composite molding method
JP2690867B2 (en) Resin composition for gas-assisted injection molding
Frącz et al. Selected properties of biocomposites on the basis of phbv with cellulose fillers
JP2002241510A (en) Thermoplastic resin molded product and method for producing the same
JP3159741B2 (en) Method for producing reshaped article containing liquid crystalline polymer
JPH0586258A (en) Molding resin composition
Heino et al. In-situ reinforced polypropylene blends

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): CA NO US

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FR GB GR IE IT LU MC NL PT SE

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
121 Ep: the epo has been informed by wipo that ep was designated in this application
122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: CA