JPH07316404A - Polyester composition and molding made therefrom - Google Patents

Abstract

PURPOSE:To obtain the title composition excellent in dispersibility of calcium carbonate particles and heat resistance. CONSTITUTION:This composition is obtained by compounding a phosphorus compound, calcium carbonate and a polyester through a vented extruder. The calcium carbonate content is preferably above 5wt.% and at most 80wt.% based on the polyester. Accordingly, a molding excellent in whiteness, hiding power and gloss can be obtained from this composition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester composition and a molded article made of the same, and more specifically to a polyester composition obtained by kneading a phosphorus compound, calcium carbonate and polyester with a vent type extruder and a film made of the same. Related to the molded articles of
More specifically, the present invention relates to a molded product such as a film and a polyester composition suitable as a base material for printing paper, X-ray intensifying screen, card, label, display board, white board and the like.

[0002]

2. Description of the Related Art Polyester represented by polyethylene terephthalate has excellent physical and chemical properties and is widely used as fibers, films and other molded articles. Among these applications, white films are used as a base material for cards, labels, display boards, white boards and the like.

Conventionally, it is well known to add a large amount of white inorganic particles to polyethylene terephthalate in order to obtain a white film. For example, Japanese Patent Publication No. 59-490
No. 1 discloses a large amount of titanium oxide and barium sulfate, and Japanese Patent Publication No. 60-30930 discloses a large amount of barium sulfate, and Japanese Patent Publication No. 60-30930 and Japanese Patent Publication No. 43-12013. Then, adding a large amount of calcium carbonate, and Japanese Patent Laid-Open No. 51-2814.
No. 1 and JP-A No. 61-209260 disclose a method of kneading an inorganic filler powder or a white inorganic pigment at a high concentration. However, in the above-mentioned conventional technology, the addition of barium sulfate is inferior in the dispersibility of particles, and when the obtained polyester is used to form a film, a film having sufficient whiteness, hiding power and gloss is obtained. I can't. On the other hand, the one to which titanium oxide is added has an excellent hiding power because of the high refractive index of the particles, but for example, 450 n
Decrease in spectral reflectance in the low wavelength region below m,
A film having sufficient whiteness cannot be obtained.

Further, polyesters containing only high concentration of calcium carbonate as disclosed in JP-B-43-12013 and JP-A-51-28141 and JP-A-61-209260 are disclosed. In the method as disclosed, when calcium carbonate is simply kneaded to a high concentration in polyester, agglomeration of particles may occur, which is not preferable because a yellowish polyester can be obtained.
When the polymer stays at a high temperature, it foams or a foreign substance is generated. Furthermore, it is difficult for a film obtained from the polyester to have sufficient whiteness and hiding power.

Further, in order to solve the above-mentioned drawbacks, JP-A-62-207337 discloses a method for producing a film by simply melt-extruding a mixture of polyester, calcium carbonate and a phosphorus compound. 6622
Japanese Patent Publication No. 2 discloses a method of adding calcium carbonate and a phosphorus compound to a polyester reaction system. However, even with these methods, it is difficult to efficiently contain calcium carbonate in a high concentration in polyester, the dispersibility of particles is not sufficient, and when the polymer stays at a high temperature, foaming or foreign matter occurs. May occur. Furthermore, it is difficult for the resulting film to have sufficient whiteness, hiding power and gloss.

[0006]

An object of the present invention is to contain a large amount of white inorganic particles in a polyester to obtain a molded article excellent in whiteness, hiding power and glossiness.
An object of the present invention is to solve the above-mentioned conventional drawbacks by using a polyester composition obtained by kneading calcium carbonate and polyester with a vent type extruder and a film made of the polyester composition.

[0007]

The above-mentioned object of the present invention is as follows: (1) A polyester composition comprising a phosphorus compound, calcium carbonate and polyester kneaded in a vent type extruder. (2) A polyester composition characterized in that the content of calcium carbonate is more than 5% by weight and 80% by weight or less with respect to the polyester. (3) It can be achieved by a molded product such as a film made of the polyester composition.

The polyester of the present invention is produced by an esterification or transesterification reaction between a dicarboxylic acid or an ester-forming derivative and a diol and a subsequent polycondensation reaction. The type of polyester is not particularly limited as long as it can be molded into a fiber, a film, or other molded products. Suitable polyesters that can be molded into fibers, films, and other molded articles are those that use aromatic dicarboxylic acid as the dicarboxylic acid component,
For example, polyethylene terephthalate, polyethylene-
p-oxybenzoate, polyethylene-1,2-bis (2-chlorophenoxy) ethane-4,4'-dicarboxylate, polyethylene-1,2-bis (phenoxy) ethane-4,4'-dicarboxylate, Examples thereof include polyethylene-2,6-naphthalenecarboxylate, polybutylene terephthalate, and polycyclohexanedimethylene terephthalate, and among them, polyethylene terephthalate is preferable. Of course, these polyesters may be homopolyesters or copolyesters, and examples of components to be copolymerized include adipic acid, sebacic acid, dimer acid, phthalic acid, isophthalic acid, and 2,6-naphthalene dicarboxylic acid. Acid, 5-sodium sulfoisophthalic acid, diphenyldicarboxylic acid, 4,4
′ -Sulfonyldibenzoic acid and other dicarboxylic acids or ester-forming derivatives thereof, trimellitic acid, pyromellitic acid and other polyfunctional carboxylic acids or ester-forming derivatives thereof, oxycarboxylic acids such as p-oxyethoxybenzoic acid or the like Ester-forming derivatives and the like, further, ethylene glycol, butanediol, propylene glycol, diethylene glycol, neopentyl glycol,
Examples thereof include p-xylylene glycol, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, and polyalkylene glycol having an average molecular weight of 200 to 20,000.

The polyester composition of the present invention is produced by kneading a phosphorus compound, calcium carbonate and polyester with a vent type extruder. The method of kneading with a vent type extruder is not particularly limited, but it is preferable to use a normal vent type single-screw or twin-screw extruder. The extrusion conditions are the melting point of the polyester or more, the residence time is within 2 hours, preferably 1 minute to 1 hour,
The vent has a vacuum of 100 tons to remove decomposed gas components and low volatile components and suppress polyester decomposition.
rr or less, preferably 10 torr or less, and further 2t
It is preferable to set it to or or less. The method of supplying the phosphorus compound, calcium carbonate and polyester to the extruder is not particularly limited, but the phosphorus compound and the polyester may be mixed and supplied in advance, or the calcium carbonate and the polyester may be mixed and supplied. Alternatively, the phosphorus compound, calcium carbonate and polyester may be separately supplied. At that time, the phosphorus compound may be supplied in the form of a solution or slurry in which water or a solvent such as alcohol is appropriately mixed.

In the present invention, since the phosphorus compound, the calcium carbonate and the polyester are kneaded in the vent type extruder as described above, some reaction may occur between the phosphorus compound, the calcium carbonate and the polyester. In addition, calcium carbonate can be efficiently contained in polyester at a high concentration without causing any foreign matter or generating foreign matter. On the other hand, in the method of kneading a phosphorus compound, calcium carbonate, and polyester with a non-vented normal single-screw or twin-screw extruder, there is no mutual reaction, the resulting polyester foams, or foreign matters are generated. Moreover, a polymer having a high degree of polymerization cannot be obtained. Further, there are problems in terms of removing decomposed gas components and low volatile components and suppressing the decomposition of polyester.

The phosphorus compound of the present invention is not particularly limited as long as the compound contains elemental phosphorus. Examples thereof include phosphoric acid, phosphorous acid, phosphinic acid, phosphonic acid and their derivatives. Specific examples include phosphoric acid, phosphorous acid, phosphoric acid trimethyl ester, phosphoric acid tributyl ester, phosphoric acid triphenyl ester, phosphoric acid mono- or dimethyl ester, phenylphosphonic acid dimethyl ester, and phenylphosphonic acid diethyl ester. it can. Further, metal phosphates such as calcium phosphate, sodium phosphate, magnesium phosphate, manganese phosphate, ammonium phosphates and the like can also be preferably used. Among these phosphorus compounds, phosphoric acid, phosphorous acid, phosphinic acid, phosphonic acid or their ester compounds are preferable, and phosphoric acid, phosphorous acid, phosphinic acid, phosphonic acid or their alkyl groups having 3 or less carbon atoms. Ester compounds are preferred, especially phosphoric acid, phosphorous acid or phosphoric acid mono-, di- or trialkyl esters. Further, two or more of these phosphorus compounds may be used in combination.

The amount of the phosphorus compound of the present invention is not particularly limited, but it is 0 with respect to calcium carbonate from the viewpoints of particle dispersibility of calcium carbonate in polyester, generation of foreign matters when polyester stays at high temperature, and foaming. It is preferably 0.01% by weight or more, more preferably 0.1 to 20% by weight, and particularly 2.
0 to 15% by weight is preferred. If the amount is less than 0.01% by weight based on calcium carbonate, the particle dispersibility of calcium carbonate in polyester may be poor, or foreign matter may be generated or foaming may occur during high temperature retention of polyester, which is not preferable.

The calcium carbonate of the present invention is more than 5% by weight and preferably 80% by weight or less, more preferably 7 to 78% by weight, further preferably 10 to 10% by weight based on the polyester.
75% by weight, particularly preferably 26 to 70% by weight.
When the content is 5% by weight or less, when the polyester composition is formed into a film, the whiteness and the hiding property of the film are insufficient, which may not be preferable. If the content exceeds 80% by weight, the particle dispersibility of calcium carbonate in the polyester is inferior, foreign matter is generated or foams when the polyester stays at high temperature, and the polyester having a high degree of polymerization cannot be obtained. In some cases, the strength is not sufficient, which is not preferable.

Calcium carbonate in the present invention is a natural product,
It may be a synthetic product, and its crystal form includes, but is not particularly limited to, calcite, anagolite, vaterite and the like. Also other metal compounds, such as
Magnesium oxide, aluminum oxide, silicon dioxide, etc. may be contained.

The particle size and specific surface area of the calcium carbonate of the present invention are not particularly limited, but the average particle size is 0.01 to 20 μm, more preferably 0.1 to 10 μm.
In particular, 0.2 to 5 μm is preferable in terms of whiteness, hiding power and gloss. The specific surface area is preferably 0.5 to 100 m ² / g, more preferably 1 to 70 m ² / g, and particularly preferably 3 to 60 m ² / g in terms of whiteness, hiding power and gloss. When the average particle size of the particles exceeds 20 μm or the specific surface area is less than 0.5 m ² / g, the particle dispersibility in the polyester is good, but when the polyester composition is formed into a film,
In some cases, the whiteness, hiding power, and gloss are inferior, which is not preferable. On the other hand, when the average particle size is less than 0.01 μm or the specific surface area exceeds 100 m ² / g, the dispersibility of particles in the polyester is remarkably deteriorated, and when the polyester stays at a high temperature, it is coarse. Foreign matter is generated,
In some cases, it is not preferable because foaming occurs, and furthermore, a polyester having a high polymerization degree cannot be obtained.

The amount of elemental phosphorus in the polyester composition of the present invention is not particularly limited, but the amount of elemental phosphorus is 10
0 to 10000 ppm is preferable, more preferably 20
0 to 9000 pm, more preferably 300 to 8000
ppm, particularly preferably 500 to 7000 ppm. If the amount of elemental phosphorus is less than 100 ppm, the particle dispersibility of calcium carbonate in the polyester may be poor, or foreign matter may be generated and foaming may occur when the polyester stays at high temperature, which is not preferable. On the other hand, if it exceeds 10000 ppm, a polyester having a high degree of polymerization cannot be obtained, which is not preferable in some cases.

In the production of the polyester composition of the present invention, polyester, other thermoplastic resins such as polyethylene, polypropylene, polystyrene, etc., and various additives such as ultraviolet absorbers, antioxidants, antistatic agents, etc. Agents, surfactants, pigments, optical brighteners, and other inorganic particles, organic particles such as titanium dioxide, barium sulfate, clay, talc, kaolin, alumina, wet and dry, inorganic particles such as spherical silica, acrylic Organic particles containing acids, styrene and the like as constituent components may be appropriately mixed as necessary.

The method for obtaining various molded articles from the polyester composition of the present invention is not particularly limited, but it is a fiber by melt spinning, various molded articles by extrusion molding or injection molding, or a sheet by melt extrusion. A film can be produced by stretching the film or stretching it. The various molded products obtained have slipperiness, glossiness,
It has excellent whiteness and hiding power.

A specific method for producing a film made of the polyester composition of the present invention will be described. After drying the polyester composition, it is melt extruded into an unstretched sheet, and then biaxially stretched and heat-treated to form a film. . Biaxial stretching may be either longitudinal or transverse sequential stretching or biaxial simultaneous stretching, and the stretching ratio is not particularly limited, but usually 2.0 to 5.0 times both longitudinal and transverse are suitable. Also,
After biaxial stretching, it may be re-stretched in either the longitudinal or transverse direction. At this time, the content of the modifier composed of calcium carbonate can be appropriately changed by mixing the polyester composition of the present invention with various polyesters. Further, various polyesters to be mixed may be the same as or different from the base polyester of the polyester composition of the present invention.

The film of the present invention can be obtained from the polyester composition by the method described above. The film of the present invention is not particularly limited, but in order to obtain a biaxially stretched film excellent in whiteness, glossiness and hiding property, the content of calcium carbonate in the film is more than 5% by weight and 40% by weight or less. And more preferably 7 to 30% by weight, especially 1
It is preferably 0 to 20% by weight. If the content of calcium carbonate is 5% by weight or less, the whiteness and the hiding property may be poor, which may not be preferable. If the content exceeds 40% by weight, the mechanical properties of the film may be inferior, which may be undesirable.
The density of the film is preferably 0.80 to 1.38 g / cm ³ . When the density is less than 0.80 g / cm ^3, the productivity and mechanical properties of the film are poor, and the density is 1.38 g / c.
If it exceeds m ³ , it may be unfavorable because of poor whiteness and hiding power.

When producing various molded articles comprising the polyester composition of the present invention, polyester, other thermoplastic resins such as polyethylene, polypropylene, polystyrene, etc., and various additives such as ultraviolet absorbers, Antioxidants, antistatic agents, surfactants, pigments, optical brighteners, and other inorganic particles, organic particles such as titanium dioxide, barium sulfate, clay, talc, kaolin,
Alumina, wet and dry type, inorganic particles such as spherical silica,
Organic particles containing acrylic acid, styrene and the like as constituent components may be appropriately blended and added as necessary.

The film of the present invention may be a composite film comprising a layer made of the polyester composition of the present invention and another polyester layer. The laminated structure at that time is not particularly limited as long as it has two or more layers.

[0023]

EXAMPLES The present invention will now be described in more detail by way of examples. The properties in the examples were measured as follows.

A. Specific surface area and particle diameter of calcium carbonate The specific surface area was measured by a BET method surface area measuring device, and the particle diameter was measured by an ultracentrifugal particle size distribution measuring device.

B. Amount of phosphorus element in polyester The polyester was wet decomposed and measured by a colorimetric method.

C. Intrinsic viscosity of polyester It was measured at 25 ° C using an o-chlorophenol solvent.

D. Particle dispersibility in polyester 20 mg of polymer is sandwiched between two coverslips 280
After melt press cooling at ℃, it was judged by microscopic observation. A: No aggregated particles or coarse particles are observed. Δ: Aggregated particles or coarse particles are slightly observed. X: Many aggregated particles or coarse particles are observed.

F. Hiding property of film The visible light transmission density of a film having a thickness of 50 μm was measured with a densitometer TD-504 manufactured by Macbeth Co., and the hiding property was obtained.
The transmission density here is calculated by the following equation. O · D = −log (T / 100) where O · D; transmission density [−] T; visible light transmittance [%]

G. Whiteness of Film 450 μm and 550 nm Thickness 50 μ Measured with Tungsten Light Source Using Hitachi Autograph Spectrophotometer EPE-2
It was calculated from the respective reflectances R ₄₅₀ and R ₅₅₀ of the film of m by the following formula.

Whiteness (%) = 4R ₄₅₀ -3R ₅₅₀

H. Gloss of Film According to JIS Z84741, the specular gloss of 60 degrees was measured, and the gloss of the film was measured.

Example 1 30 parts by weight of calcium carbonate powder having an average particle size of 1.2 μm and a specific surface area of 8.0 m ² / g and an intrinsic viscosity of 0.65 dl /
g of polyethylene terephthalate chips (70 parts by weight), and then fed to a vented twin-screw extruder using a feeder, and then 5 parts by weight of trimethyl phosphate as a phosphorus compound with respect to calcium carbonate from an injection nozzle installed in the extruder. % So as to be added. 10 ton vent
The vacuum degree of r was maintained, and the mixture was kneaded at a temperature of 290 ° C. for a residence time of 5 minutes to obtain polyethylene terephthalate containing 30% by weight of calcium carbonate. No foreign matter is generated during kneading,
No foaming was observed. The particle dispersibility of calcium carbonate in the obtained composition was also good. Furthermore, the amount of elemental phosphorus in the composition was measured by a colorimetric method to be 1
It was 700 ppm.

Polyethylene terephthalate containing 30% by weight of the obtained calcium carbonate and an intrinsic viscosity of 0.65 d
1 / g of polyethylene terephthalate was mixed so that calcium carbonate would be 15% by weight, and 0.02 part by weight of an optical brightening agent "OB-1" (manufactured by Eastman) was added to 100 parts by weight of the total polyester. Then, after sufficiently drying, it was supplied to an extruder, melted at 290 ° C., extruded in a sheet form from a T-shaped die, and cooled and solidified by a cooling drum at 30 ° C. to obtain an unstretched film. Then, the unstretched film is heated to 95 ° C. and stretched 3.3 times in the machine direction, and further stretched by 10 times.
The film was heated to 0 ° C., stretched 3.3 times in the transverse direction and heat-treated at 200 ° C. to obtain a film having a thickness of 50 μm. Table 1 shows the characteristic results of the obtained film. Density is 1.28 g /
In cm ³ , the whiteness, hiding power and gloss were excellent.

Comparative Example 1 Calcium carbonate 30 was prepared using a vented twin-screw extruder in the same manner as in Example 1 except that the phosphorus compound was not added.
A polyethylene terephthalate and film containing wt% were obtained. When polyethylene terephthalate containing 30% by weight of calcium carbonate was produced using a vented twin-screw extruder, foaming occurred in the polymer and the particle dispersibility of calcium carbonate was poor. Further, the film was severely torn due to foaming, and the obtained film was inferior in whiteness, hiding power and gloss.

Examples 2 to 11 As shown in Tables 1 and 2, polyester compositions and films were obtained in the same manner as in Example 1 except that the type and amount of calcium carbonate and the type and amount of phosphorus compound were changed. . Tables 1 and 2 show results of various characteristics.

Examples 2 to 11 were within the scope of the present invention, the particle dispersibility of calcium carbonate in the obtained polyester was good, and the film was excellent in both whiteness and hiding power.

[0037]

[Table 1]

[Table 2]

[0038]

As described above, the present invention is a polyester composition obtained by kneading a phosphorus compound, calcium carbonate and polyester in a vent type extruder, which is a polyester composition excellent in dispersibility of calcium carbonate particles and heat resistance. It is possible to obtain a molded product, and a molded product excellent in whiteness, hiding power and glossiness can be obtained from the polyester composition. In particular, when a polyester composition is formed into a film, a white film excellent in whiteness, hiding power, and gloss can be produced, and it can be used for printing paper, X-ray intensifying screens, cards, labels, display boards, white boards, etc. It is preferably used as a base material.

Claims (9)

[Claims] 1. A polyester composition obtained by kneading a phosphorus compound, calcium carbonate and polyester with a vent type extruder. 2. The polyester composition according to claim 1, wherein the phosphorus compound is at least one selected from the group consisting of phosphoric acid, phosphorous acid, phosphinic acid, phosphonic acid, and ester compounds thereof. object. 3. The phosphorous compound is at least one selected from the group consisting of phosphoric acid, phosphorous acid, phosphinic acid, phosphonic acid, and alkyl ester compounds thereof having 3 or less carbon atoms. Item 3. The polyester composition according to Item 1 or 2. 4. The amount of phosphorus compound is 0.01% by weight or more with respect to calcium carbonate.
The polyester composition according to any one of 3 above. 5. The polyester composition according to any one of claims 1 to 4, wherein the content of calcium carbonate is more than 5% by weight and 80% by weight or less with respect to the polyester. 6. The polyester composition according to claim 5, wherein the phosphorus element content in the polyester composition is 100 to 10,000 ppm. 7. A molded article made of the polyester composition according to claim 1. 8. A film comprising the polyester composition according to claim 1. 9. A white film, wherein the film according to claim 8 is white.