JPH02110156A - Fluororesin molding - Google Patents

Abstract

PURPOSE:To obtain a molding having a decreased coefficient of linear expansion and improved mechanical properties and moldability without detriment to the excellent weathering resistance, chemical resistance, abrasion resistance and staining resistance, etc., inherent in fluororesins by mixing a specified fluororesin with a liquid crystal polymer and molding the mixture. CONSTITUTION:A fluororesin (A) selected from among polychlorotrifluoroethylene, an ethylene/tetrafluoroethylene copolymer, a tetrafluoroethylene/hexafluoropropy lene copolymer and a perfluoroalkoxy fluororesin is mixed with a polymer (B) showing an anisotropic molten state (e.g., a copolymer of polyethylene terephthalate with p-hydroxybenzoic acid) in a component A to component B ratio of 60:40-97:3 (by weight). The addition of component B, makes it possible to obtain the title molding having a markedly decreased coefficient of linear expansion and excellent mechanical properties and moldability without detriment to the excellent weathering resistance, chemical resistance, abrasion resistance, staining resistance, etc., inherent in component A.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a Furi S-based ellipsoid molded article having a reduced coefficient of thermal expansion and excellent mechanical properties and moldability.

(Prior art) Fluorine resins such as polychlorotrifluoroethylene, ethylene-tetrafluoroethylene copolymer, tetrafluoroethylene-hexabutylene propylene copolymer, and non-fluoroalfoxy fluororesin are shown in Table 1. It can be used over a wide range of temperatures as shown in Figure 2, and has good moldability.

It has excellent chemical resistance, alkali resistance, acid resistance, water resistance, weather resistance, corrosion resistance, abrasion resistance, electrical insulation, etc., so it can be used as a lining material for pumps, flexible tubes, films, etc. It is used in a wide range of applications such as hearth baskets, pump impellers, mechanical parts, and chemical laboratory equipment.

However, since fluororesin has a large linear expansion coefficient, it may undergo thermal changes when used under conditions of rapid temperature changes or in high-temperature areas.

Therefore, it is difficult to apply fluororesin molded bodies to parts that require high precision, especially in the electronics field, and to eaves and lining materials used in chemical equipment.

In order to reduce the linear expansion coefficient of the molded product (to make it a composite molded product with asbestos, etc.), use metal materials and fiber reinforced plastics (F
It is conceivable to form a laminate with RP). However, in such composite molded bodies, even if a large amount of filler is used, the coefficient of linear expansion of the fluororesin cannot be sufficiently reduced, and on the contrary, the excellent surface properties ( (friction and wear characteristics) are impaired.

On the other hand, in the case of laminates, although this is solved physically, new problems arise, such as an increase in weight due to lamination, delamination due to increasing coefficient of linear expansion, and reduced flexibility in molding processability. .

(Problems to be Solved by the Present Invention) The present invention solves the above-mentioned conventional problems, and its purpose is to improve the excellent weather resistance, chemical resistance, and abrasion resistance of the fuss-based resin. The object of the present invention is to provide a fluororesin molded article which has a significantly reduced coefficient of linear expansion without impairing properties such as stain resistance, and also has excellent mechanical properties and moldability.

(Means for solving the problem) The fluororesin used in the present invention is polychlorotrifluoroethylene, ethylene-tetrafluoroethylene copolymer, tetrafluoroethylene-hexafluoroglobylene co-11 polymer, and Hino I The above polychlorotrifluoroethylene may be one that can be broken by ordinary melt molding, and its degree of polymerization is from 500 to 3,000.
It is preferable that the degree of

The above ethylene-tetrafluoroethylene copolymer is a copolymer of ethylene and tetrafluoroethylene, and the copolymerization ratio is 8.
:2 to 2:8 is preferred.

The above-mentioned tetrafluoroethylene-hexafluoropropylene copolymer is a copolymer of tetrafluoroethylene and hexafluoropropylene, and the content of hexafluoropropylene is 10 to 20 mo1%.
is preferred.

The above E/'-fluoroalkoxyfluororesin is a copolymer of tetrafluoroethylene and/(-fluoroalkyl vinyl ether), and the content of the fluoroalkyl vinyl ether is preferably 1 to 10 mo1%, and the alkyl group has 1 carbon number. ~10 is preferred.

Polymer (b) exhibiting anisotropic melt morphology used in the present invention
Examples of the liquid crystal polymer (hereinafter referred to as liquid crystal polymer) include aromatic-aliphatic polyesters, wholly aromatic polyesters, aromatic polyazomethines, polyimide esters, and among these, compounds exhibiting an anisotropic melt morphology are selected. Aromatic-
Examples of aliphatic polyesters include copolymers of polyethylene terephthalate and parahydroxybenzoic acid. Examples of wholly aromatic polyesters include copolymers of hydroxybenzoic acid and 6-hydroxy-2-7-toic acid; There are copolymers.

As the aromatic polyazomethine, for example, polytrilo-2-methyl-1,4-phenylenenitroethyriteine-
1,4-7 22lene ethylidene), etc. As the polyimide ester, for example, a copolymer of 2,6-s7tale dicarboxylic acid, terephthalic acid and 4(4'-hydroxyphthalimide)phenol, or a diphenol 4
- Copolymers derived from (4'-hydroxy 7-talimide) benzoic acid, etc.

In order to determine whether these copolymers are liquid crystal polymers, it is preferable to utilize the fact that liquid crystal polymers can exhibit optical anisotropy in a molten state.

Optical anisotropy t1, normal polarization! This can be confirmed by using a lll-mirror. For example, place a test piece adjusted to a thickness of 1 inch or less on a heating stage, and heat it for 2 hours under a nitrogen atmosphere.
Heating is continued at a temperature increase rate of approximately ℃/starting temperature. In this state, the polarizer of the polarizing microscope and the analyzer are crossed at right angles, and
A11 drive can be easily detected by observing at a magnification of 00x. In such a method, it is also possible to simultaneously measure the temperature at which these copolymers transition to a liquid crystal phase. This may also be measurable by thermal analysis (eg, DSC%TMA, etc.).

As the liquid crystal polymer, a polymer exhibiting an anisotropic melt morphology in the molding temperature range of the fluorine column gr1- shown in Table 1 is preferably used.

In other words, the molded article of the present invention can exhibit an anisotropic melt morphology (i.e., can be melted) within a humidity range that partially overlaps the temperature range in which the fluororesin melts without thermal decomposition. ) is preferably composed of a liquid crystal polymer.

This is because, as a means for producing a molded article in the present invention,
This is because a method is generally used that includes a step of dispersing the above compositions in a molten state. In such a method, if either the fluororesin or the liquid crystal polymer constituting the composition undergoes thermal decomposition, the physical properties of the obtained molded product will deteriorate, so this is not preferred. do not have. As mentioned above, the molding temperature of fluororesin is 300
~400'C, so it is preferable to select a liquid crystal polymer that can be molded in this temperature range. Therefore, among the above liquid crystal polymers, aromatic-aliphatic polyesters and wholly aromatic polyesters are particularly suitable.

The above-mentioned molded body made of liquid crystal polymer alone usually has excellent mechanical properties (eg, strength, elastic modulus, and impact strength). Furthermore, molded bodies obtained by injection molding or extrusion molding exhibit enhanced mechanical properties due to the orientation of the polymer molecules parallel to the flow direction of the resin during melting. This is a self-reinforcing effect because the liquid crystal polymer exhibits an anisotropic melt morphology, and the degree of reinforcement is controlled by the degree of orientation of the polymer molecules.

That is, the mechanical properties of a melt molded body of a liquid crystal polymer often differ depending on the molding method and/or the shape of the molded body. Furthermore, for the same reason, molded bodies of liquid crystal polymers exhibit significant anisotropy in terms of mechanical properties. In addition, since the liquid crystal polymer has a linear molecular structure, it usually has an extremely small coefficient of linear expansion (coefficient of thermal expansion). Moreover, it has been recognized that in molded bodies, the value is even smaller in the direction parallel to the flow. Since the fluororesin molded article of the present invention contains a liquid crystal polymer having such characteristics and a fluororesin, the coefficient of linear expansion is lower than that of a molded article made only of fluororesin. The body also has excellent mechanical properties and moldability.

Fluorine resin (
The weight ratio of a) and liquid crystal polymer (bl is 6°:40-9
The ratio is 7:3, preferably 70:30 to 95:5. If the content of the liquid crystal polymer is less than 5% by weight, no effect of reducing the coefficient of linear expansion can be expected. In addition, when it approaches 40% by weight, the effect converges to a constant value, and when it exceeds 40% by weight,
LCD poly! This is because the fibrils of - are difficult to miniaturize, making it impossible to obtain physical compactness of the molded article.

Furthermore, in the second invention, polyarylate,
One or more polymers (containing Cl) selected from the group consisting of polyethylene terephthalate and polycarbonate. Polymer (c) improves the compatibility between the fluororesin and the liquid crystal polymer.

The compatibility between fluororesin and liquid crystal polymer is small at the interface, but adding the above polymer improves the compatibility.
The molded product becomes denser and its surface smoothness and mechanical properties improve.

The above polyarylate is a copolymer of bisphenol A and terephthalic acid or isophthalic acid. The polyarylate may be of any type as long as it can be melt-molded, but its molecular weight is between 1000 and 40. It is preferable that it is about OOO.

The above-mentioned polyethylene terephthalate is a linear polyester represented by the following formula, and has a molecular weight of 1000 to 40.
OOOO is preferable.

The above-mentioned polycarbonate has carbon in its main chain, and polymer compounds represented by the following formula are preferably used, and those obtained from the reaction of bisphenol A and phosgene are particularly preferred. Further, the molecular weight is preferably 2000 to 40,000.

(In the formula, R1 is a phenylene group,) represents a rhodane or alkyl-substituted phenylene group or a naphthylene group, and R1 represents hydrogen or an alkyl group having 10 or less carbon atoms. ) 1 to 100 parts by weight of the total amount of the above polymer (Cl ratio is fluorine yF, m fat!a) and liquid crystal polymer fbl.
The amount is 20 parts by weight, preferably 2 to 10 parts by weight.

When the amount of IJ-r- added decreases, the effect of improving the compatibility between the fluororesin and the liquid crystal polymer disappears, and 20
If the amount exceeds 1 part by weight, the excellent properties of the fluororesin, such as chemical resistance and weather resistance, will be impaired.

In addition, in the present invention, for the purpose of slightly improving physical properties and stabilizing moldability, glass fibers, inorganic fillers, modifiers,
A lubricant, a heat stabilizer, a warming agent, etc. may be added.

The fluororesin molded article of the present invention is produced by melt molding into a membrane. Such manufacturing methods include any molding method that molds a melt of a polymer blend of a fluororesin, a liquid crystal polymer, and a polymer.

For example, fluorine resin, liquid crystal polyester! - and polymers are melted, mixed, and subsequently molded by extrusion molding, blow molding, injection molding, calender molding, etc.

During such molding, it is often observed that the liquid crystal polymer easily forms a fibrillar shape by being subjected to extensional flow or shear flow in the molten state, and that the long axes of the polymers are substantially aligned parallel to each other. . This degree of fibril orientation is effective in reducing the coefficient of linear expansion.

Therefore, it is useful to use a means to promote fibrillation of the liquid crystal polymer and increase the degree of fibril orientation. For example, in extrusion molding, it is effective to arrange a static mill in series with the molding machine. This is in order to efficiently add elongation flow and shear flow to the liquid crystal polymer t which is in a liquid crystal state when the blend sufficiently dispersed in the extruder passes through the static mill. For the same reason, it is useful to provide the extruder head with a breaker having relatively small diameter passages, and to provide a mesh with a mesh diameter of about IJrl11 or less. This is a method of increasing the tensile force by providing a constricted passage in the flow path of the molten resin, generating a pressure gradient when the fluid passes through the passage, and giving a velocity distribution, especially in the streamline direction. Furthermore, stretching the molded product in one or two axes until it cools and solidifies is the best way to use liquid crystal polyester! This is an extremely effective means because the fibrillation of - becomes significant. In addition, in injection molding, fibrillation of liquid crystal polymer can be expected to some extent even with the in-film method, but if further improvement is expected,
Increasing the shear rate of the resin within the mold (e.g. increasing the injection speed, making the nozzle or spool conical, increasing the length/thickness ratio (L/T) of the mold), etc. is valid.

In the molded product obtained by straining, the long fibers (fibrils) of the liquid crystal polymer are uniformly dispersed in the fluororesin, so the linear expansion is smaller than that of a molded product made only of fluororesin. Moreover, the molded body has improved mechanical properties because when the liquid crystal polymer takes the fibrillar form, the molecules of the polymer are in the highest oriented WA, resulting in a larger elastic modulus and a smaller This is because it has a coefficient of linear expansion (sometimes showing a negative value) and is considered to be particularly effective in reducing the coefficient of linear expansion of a molded article containing a liquid crystal polymer.The fibrils of the liquid crystal polymer are preferably , whose diameter is 10
0 μm or less. In particular, the larger the average length/diameter ratio (L/D) of the fibrils, the more effective it is, preferably 10 or more, more preferably 100
or more.

Because the fibrils of the liquid crystal polymer having such a shape are dispersed, the coefficient of linear expansion of the fluororesin molded article exhibits a sufficiently lower value than that of a molded article made only of fluororesin. Further, it is preferable that the fibrils are substantially uniaxially oriented in the molded article because the coefficient of linear expansion in this direction is selectively reduced.

The fluororesin molded article of the present invention is molded into a desired shape such as a sheet, rod, film, pipe, fiber, or block. The molded product of the present invention can be used in plant parts such as pipes, tubes, films, lining materials, valve seats, filters, etc. used under various strong acids and solvents, machine parts, etc.
It is used in a wide range of applications such as electronic components.

(Example) Next, the present invention will be explained in detail.

Examples 1 to 4, Comparative Example 1.2 A predetermined amount of polychlorotrifluoroethylene (
Manufactured by Daikin: Dai70-inch CTFE, ΩCTFE in the table)
, fully aromatic polyester+! Crystalline polymer (manufactured by Polyplastics: VECTRA A950, LCP in the table)
), and polycarbonate (manufactured by Teijin Kasei Co., Ltd.: Henrite L-1225, pc in the table) were sufficiently dried, then fed to a twin-screw kneading extruder, and the two or three components were melted at a resin temperature of 330°C. After thorough kneading, the mixture was extruded into a strand-like molded product with a length of about 3 diameters, and cut into lengths of about 4 fins using a pelletizer to obtain pellets. The obtained pellets were fed into a 25 mm single screw extruder and molded into a sheet-like molded product. Here, the resin temperature in the extruder cylinder is 330°C, and the screw rotation speed is 40r.
It was pm. Further, the opening dimensions of the molding die of the extruder were 3 mm thick, 50 ms wide, and the set temperature was 290°C. A water tank for cooling the molded body and a roll take-up machine for taking up the molded body were installed on the extension line of the extruder in the extrusion direction, and the molded body was stretched by changing the take-up speed of the take-off machine.

Note that the stretching ratio was calculated using the following formula.

The obtained sheet-like molded body was dissolved in dimethylacetamide, and the average length (L) of the liquid crystal polymer fibrils was measured from a polarized light micrograph (100x magnification) of the cut fibrils, and an electron micrograph of the cross section of the molded body ( The diameter (D) of the fibril was measured from a magnification of 1000 times, and L/D was determined.

Bow tension test M (AS
TM D 638), and the coefficient of linear expansion in the same direction (based on ASTM D696) was measured. The results obtained are shown in Table 2.

(Left below) Ron ETFE, ETFE in the table), fully aromatic polyester liquid crystal poly! - (Manufactured by Polyplastics: VECTR
After thoroughly drying A950 (LCP in the table) and polycarbonate (manufactured by Konjin Kasei Co., Ltd.) and Hannrite L-1225 (pc in the table), the two components were mixed at a resin temperature of 310°C using a twin-screw kneading extruder. Alternatively, the three components were sufficiently melt-mixed and extruded as a strand-like molded product with a diameter of about 3B, which was then cut into a length of about 4vrsC using a pelletizer to obtain a pellet. Example 1 except that the obtained pellet was used, the resin temperature in the extruder cylinder was 330°C, and the temperature setting of the molding die was 300°C.
A sheet-like molded product was obtained in the same manner as in Example 1, and its physical properties were measured. The results are shown in Table 3.

(Margins below) Examples 5 to 8, Comparative Example 3.4 Ethylated ethylene copolymer in a predetermined amount shown in Table (2) (manufactured by Daikin Co., Ltd., Yofu Neo 7, Neoflon FEP% FEP in the table) , fully aromatic polyester liquid crystal polymer (manufactured by Polyplastics, VE
CTRA, A950. LCP in the table) and polycarbonate (manufactured by Konjin Kasei Co., Ltd.:) Denlight L-1225,
After thoroughly drying the PC in the table, using a twin-screw kneading extruder, the two or three components were sufficiently melt mixed at a resin temperature of 350°C and extruded as a strand-shaped molded product with a feed diameter of about 3. Using a pelletizer, it was made into a length of about 4f.
i to obtain pellets. Using the obtained pellet, a sheet-shaped molded product was obtained in the same manner as in Example 1, except that the resin temperature in the extruder cylinder was set at 340°C and the temperature set in the molding die was set at 320°C. was measured and the results are shown in Table 4.

(Left space below) Examples 9 to 12, Comparative Example 5.6 Predetermined amount of tetrafluoroethylene hexafluoride 7' shown in Table ■
Robylene copolymer (Daikin PFA, PFA in the table)
, fully aromatic polyester liquid crystal polymer (manufactured by Polyplastics Co., Ltd., VECTRA A950, LCP in the table) and polycarbonate (manufactured by Ryotai Kasei Co., Ltd., Panlite L-1
225, pc in the table), and the same 11 as carried out in Example 9.
1C to obtain a beret. Using the resulting beret,
A sheet-shaped molded product was obtained in the same manner as in Example 1, except that the resin temperature in the extruder cylinder was 350°C and the temperature of the molding guide was 333°C, and the physical properties were measured.
The results are shown in Table 5.

(Leaves below) Examples 13 to 16, Comparative Example 7.8 A predetermined amount of perfluoroalkoxy fluororesin shown in Table i0 (manufactured by Guikin, Neo 70) Characteristics such as chemical resistance, abrasion resistance, stain resistance, etc. It has a significantly reduced coefficient of linear expansion, excellent surface properties, and excellent mechanical properties and moldability without impairing the properties.

Therefore, the molded product of the present invention can be used under various strong acids and solvents), plant parts such as tubes, films, lining materials, valve seats, filters, etc., machine parts, etc.
Wide range of applications such as electronic parts: FI5. used.

Claims (1)

[Claims] 1. (a) selected from the group consisting of polychlorotrifluoroethylene, ethylene-tetrafluoroethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and perfluoroalkoxyfluororesin (b) a polymer exhibiting an anisotropic melt morphology, the fluororesin (a)
and a polymer (b) in a weight ratio of 60:40 to 97:3. 2, (a) a fluororesin selected from the group consisting of polychlorotrifluoroethylene, ethylene-tetrafluoroethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and perfluoroalkoxyfluororesin; , (b) a polymer exhibiting an anisotropic melt morphology, and (c) one or more polymers selected from the group consisting of polyarylate, polyethylene terephthalate, and polycarbonate, comprising a fluororesin (a) and a polymer (b). ) is 60:40 to 97:3, and the polymer (
A fluororesin molded article containing 1 to 20 parts by weight of c).