JPH04214758A - Polyester composition - Google Patents

Abstract

PURPOSE:To provide a polyester composition capable of forming a molded article having small void volume and excellent slipperiness and especially abrasion resistance. CONSTITUTION:The objective polyester composition is produced by compounding a polyester with 0.005-5wt.% of composite particle obtained by covering the surface of an organic polymer particle or inert inorganic particle having an average particle diameter of 0.05-5mum with fine particles of crosslinked polystyrene by melting. The ratio of the average particle diameter of the polystyrene particle to that of the core particle is <=1/5.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a polyester composition suitable for molding polyester molded products, particularly polyester films, polyester fibers, etc., and more particularly, it relates to a polyester composition that contains specific composite particles and has excellent slip properties and abrasion resistance. The present invention relates to a polyester composition capable of forming molded articles.

0002

[Prior Art] In general, polyester, particularly polyethylene terephthalate or polyethylene naphthalate,
Because of its excellent mechanical and chemical properties, it is widely used in films, fibers, etc.

[0003] However, when producing a film or fiber that takes full advantage of its transparency and glitter,
In the molding and processing steps, process defects often occur. This is often due to a high coefficient of friction.

Conventionally, many methods have been proposed to reduce the friction coefficient of polyester, including the presence of inert particles in polyester. Both the slipperiness and abrasion resistance of the material were unsatisfactory.

To explain this method more specifically, as a means of improving the surface properties of polyester, conventionally,
A method in which part or all of the catalyst used during polyester synthesis is precipitated in the reaction process (internal particle precipitation method) ■ A method in which particles such as calcium carbonate or silicon oxide are added during or after polymerization (external particle addition method) Many have been proposed.

[0006] However, the internal particle precipitation method (2)
Since the particles are metal salts of polyester components, they have a certain degree of affinity with polyester, but on the other hand, since the method generates particles during the reaction, it is difficult to control the particle amount and diameter, and prevent the generation of coarse particles. is difficult.

On the other hand, in the method (2) of adding external particles, if the particle size, amount added, etc. are appropriately selected, and if coarse particles are further removed by classification or the like and particles are added, excellent slipperiness can be achieved. However, in terms of wear resistance, there are problems such as acceleration of wear due to fallen particles.

Surface treatment using a coupling reaction between a silane compound or a titanate compound and inorganic particles has been proposed as a means of improving the affinity of additive particles for polyester, but the treatment process is complicated and the effectiveness is limited. There are various problems such as not being as expected.

Furthermore, there is a method of attaching silica to inorganic particles as disclosed in JP-A No. 63-162728;
202671, a method for surface modification of inorganic particles found in the method of adsorbing and coating silicone, etc., JP-A-63-3
A method of coating with titanium hydrated oxide or titanium oxide as in No. 04047, or JP-A-64-1686
Surface modification methods for organic particles, such as coating them with silicon oxide as in No. is the current situation.

0010

[Problems to be Solved by the Invention] In view of the above-mentioned circumstances, the present inventors aimed to obtain a polyester composition suitable for molding a molded article with excellent slip properties, abrasion resistance, and in some cases transparency. As a result of extensive research, we discovered that a polyester composition containing composite particles in which the surface of organic polymer particles or inert inorganic particles are fused and coated with cross-linked polystyrene fine particles has excellent properties, and we have arrived at the present invention. did.

[0011] Accordingly, an object of the present invention is to provide a polyester composition that can form molded articles with small voids and excellent slip properties, particularly abrasion resistance.

0012

Means for Solving the Invention According to the present invention, the surface of organic polymer particles or inert inorganic particles having an average particle size of 0.05 to 5 μm has an average particle size relative to the average particle size. This is achieved by a polyester composition characterized in that it contains composite particles that are fused and coated with crosslinked polystyrene fine particles having a ratio of 1/5 or less.

The polyester in the present invention is a polyester containing an aromatic dicarboxylic acid as the main acid component and an aliphatic glycol as the main glycol component. Such polyesters are substantially linear and have film or fiber forming properties, particularly by melt molding.

Examples of aromatic dicarboxylic acids include terephthalic acid, naphthalene dicarboxylic acid, isophthalic acid, diphenylethanedicarboxylic acid, diphenyldicarboxylic acid, diphenyl ether dicarboxylic acid, diphenylsulfone dicarboxylic acid, diphenylketone dicarboxylic acid, anthracene dicarboxylic acid, and the like. can be mentioned.

Examples of aliphatic glycols include polymethylene glycols having 2 to 10 carbon atoms such as ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, decamethylene glycol, etc., or cyclohexanedimethanol. Examples include alicyclic diols.

[0016] In the present invention, the polyester is
For example, those containing alkylene terephthalate and/or alkylene naphthalate as a main component are preferably used.

Among such polyesters, for example, not only polyethylene terephthalate and polyethylene-2,6-naphthalate but also, for example, 80 mol% or more of the total dicarboxylic acid component is terephthalic acid and/or 2,6-naphthalate.
Preferably, the copolymer is 6-naphthalene dicarboxylic acid and 80 mol% or more of the total glycol component is ethylene glycol.

In this case, up to 20 mol % of the total acid component can be the above-mentioned aromatic dicarboxylic acids other than terephthalic acid and/or 2,6-naphthalene dicarboxylic acid, and also fatty acids such as adipic acid, sebacic acid, etc. group dicarboxylic acids; alicyclic dicarboxylic acids such as cyclohexane-1,4-dicarboxylic acid;

Further, 20 mol% or less of the total glycol component can be the above-mentioned glycols other than ethylene glycol, and for example, hydroquinone, resorcinol,
, 2-bis(4-hydroxyphenyl)propane, etc., aliphatic diols having an aromatic ring such as 1,4-dihydroxymethylbenzene; polyalkylenes such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, etc. Glycol (
Polyoxyalkylene glycol) and the like can also be used.

[0020] Furthermore, the polyester in the present invention includes:
Aromatic oxyacids such as hydroxybenzoic acid; ω-
Also included are those in which a component derived from an oxycarboxylic acid such as an aliphatic oxyacid such as hydroxycaproic acid is copolymerized or combined in an amount of 20 mol % or less based on the total amount of the dicarboxylic acid component and the oxycarboxylic acid component.

Furthermore, the polyester of the present invention contains a trifunctional or higher functional polycarboxylic acid or a polyhydroxy compound, such as a trimellitic acid, in an amount within a substantially linear range, for example, an amount of 2 mol % or less based on the total acid component. Copolymers of acids, pentaerythritol, etc. are also included.

Furthermore, the polyester in the present invention includes:
For example, additives such as pigments, dyes, ultraviolet absorbers, heat stabilizers, light stabilizers, antioxidants, light shielding agents (eg, carbon black, titanium dioxide, etc.), etc. may be included as necessary.

[0023] The organic polymer particles or inert inorganic particles in the present invention are not limited in type or manufacturing method as long as their surfaces can be fused and coated with crosslinked polystyrene fine particles.

Preferred organic polymer particles include particles of silicone resin, polystyrene resin, styrene-acrylic acid crosslinked resin, polytetrafluoroethylene resin, polyphenyl ester resin, and the like. Among these, silicone resins and polyphenyl ester resins are particularly preferred, as they tend to have improved physical properties.

[0025] As the inert inorganic particles, particles of carbonates, sulfates, silica, titanium dioxide and the like are particularly preferred. Examples of carbonates and sulfates include calcium carbonate, barium carbonate, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate, barium sulfate, aluminum sulfate, and the like. Among these, particularly preferred are calcium carbonate and barium sulfate. In addition, silica can be used, for example, by dry method or wet method (dealing method of sodium silicate, hydrolysis of alkoxysilane,
Preferably, titanium dioxide is produced by a chlorine method, a sulfuric acid method, or an alkoxy titanium hydrolysis/condensation method. In the case of silica, it may contain 30% or less of an aluminum component. Although the shape of the particles is not particularly limited, it is preferable that the particles have a spherical shape as much as possible.

[0026] As for spherical particles, when defined by the following volume shape coefficient φ (Equation 1),

[0027]

[Equation 1] [Here, V is the volume of the particle (μm3), and d is the maximum diameter (μm) in the projection plane. ]φ is 0.30 to π/
It is preferable that it be in the range of 6. In addition, φt of the entire particle group is expressed as the number average of φ of each particle, and φ
It is preferable that t is 0.40 to π/6.

Further, the relative standard deviation (Equation 2) of the spherical particles defined below is preferably 0.7 or less, more preferably 0.5 or less.

[0029]

[Formula 2] [Here, Di: the maximum diameter of each particle (μm), D: the number average value of the maximum diameter of the particles (μm), and n: the number of particles. ] The average particle diameter of the organic polymer particles and inert inorganic particles is 0.
05 to 5.0 μm, preferably 0.05 to 3.0 μm. If the average particle size is smaller than 0.05 μm, the effect of improving slipperiness and abrasion resistance is insufficient, which is not preferable. On the other hand, if the thickness is larger than 5.0 μm, coarse protrusions may be formed on the film surface, which is not preferable.

[0030] Here, the average particle size means the "equivalent spherical diameter" of particles at a point of 50% by weight of all measured particles. This "equivalent spherical diameter" means the diameter of an imaginary sphere having the same volume as the particle, but if true spherical particles are used, it is the weighted average diameter. The average particle size can be calculated from electron micrographs of the particles or measurements by conventional sedimentation methods.

These organic polymer particles or inert inorganic particles may be used alone or in combination of two or more. It may also be used in the form of a complex salt.

[0032] As a method for fusion-coating crosslinked polystyrene fine particles on the surface of organic polymer particles or inert inorganic particles, a dry method is preferably used, but other methods may be used.

[0033] Examples of the dry method include methods using mechanochemical reactions. More specifically, a predetermined amount of organic polymer particles and/or inorganic particles and crosslinked polystyrene fine particles are mixed, energy is applied using a ball mill, vibration mill, jet mill, Henschel mixer, etc., and the organic polymer particles or inert inorganic particles are mixed. An example of this method is to fuse and coat the surface of cross-linked polystyrene fine particles.

In the present invention, the average particle size of the crosslinked polystyrene fine particles must be 1/5 or less of the average particle size of the organic polymer particles or inert inorganic particles, preferably 1/5 or less. 10 or less. When this particle size ratio exceeds 1/5, the number of crosslinked polystyrene fine particles that can be fused per organic polymer particle or inert inorganic particle decreases, and the crosslinked polystyrene fine particles are not fused to organic polymer particles. or inert inorganic particles become present;
Undesirable.

The average particle size of the crosslinked polystyrene fine particles is 0.
The thickness is preferably 0.005 μm or more and 1.0 μm or less. When the average particle size of crosslinked polystyrene exceeds 1.0 μm,
The particle size ratio exceeds 1/5, which is undesirable, and on the other hand, fine particles with a diameter of less than 0.005 μm are difficult to produce or obtain industrially.

Crosslinked polystyrene fine particles are made of a monovinyl compound having one aliphatic unsaturated bond in the molecule, such as styrene, alkyl-substituted styrene, etc., and two or more aliphatic unsaturated bonds in the molecule as a crosslinking agent. It can be obtained by copolymerizing divinyl compounds having a bond, such as divinylbenzene and divinylsulfone. The polymerization for copolymerization is preferably initiated by using a radical initiator such as azoisobutyronitrile, cumene hydroperoxide, or benzoyl peroxide, or by ultraviolet irradiation because it is simple.

[0037] The amount of fused coating of crosslinked polystyrene fine particles is:
0.0 for organic polymer particles or inert inorganic particles
A range of 0.02 to 10% by weight is preferred. Especially 0.02~1
A weight percent range is preferred.

[0038] The coverage amount of crosslinked polystyrene fine particles is 0.0
If it is less than 0.02% by weight, the effect of improving the affinity between the organic polymer particles or inert inorganic particles and the polyester will not be exhibited, which is not preferable. On the other hand, if it exceeds 10% by weight, the affinity improvement effect will reach a plateau and coarse particles will be formed due to aggregation of organic polymer particles and inert inorganic particles, which is not preferable.

[0039] In the present invention, the amount of composite particles added, in which the surfaces of organic polymer particles or inert inorganic particles are fused and coated with crosslinked polystyrene fine particles, is 0 to the polyester.
．． 0.005 to 5% by weight is preferred, and more preferably 0.01 to 3% by weight.

If the added content is less than 0.005% by weight, the number of particles in the polymer is too small, resulting in, for example, a small number of protrusions on the film surface, resulting in insufficient slipperiness and abrasion resistance. On the other hand, if the added content exceeds 5.0% by weight, particle aggregation tends to occur in the polymer, making it unsuitable in terms of the number of coarse protrusions.

In the present invention, it is preferable to remove coarse particles from the composite particles using a purification process before incorporating them into polyester. Examples of the classification means include wet or dry centrifuges, filter filtration, and the like. Note that two or more of these methods may be used in combination to perform stepwise purification.

[0042] Composite particles can be incorporated into polyester at any time and by any method, but powder may be added to the molten polymer after polymerization using a screw-type twin-screw kneading extruder, a Banbury mixer, etc., and then kneaded. A preferable addition method is to perform the following. Of course, as a general method, it may be added as a glycol slurry before the polymerization reaction of the polyester reaction, particularly before the end of the transesterification or esterification reaction.

[0043] Polyester molded products, such as fibers and films, can be obtained by spinning the above-mentioned polyester composition as it is or by diluting it with another polyester (polyester that does not contain composite particles in a predetermined proportion) and then spinning or forming a film. can. Other polyesters used for dilution include:
Mention may be made, for example, of polyesters produced by conventional precipitation or addition methods or particle-free polyesters. In any case, it is necessary that the final molded product contains a predetermined amount of composite particles.

The polyester composition of the present invention can be made into molded products such as films and fibers by known methods.

[0045] In the case of a film, film formation is performed by a known method, for example, usually by melt extrusion into a sheet at 280 to 300°C, rapidly solidifying it to form an amorphous sheet, and then forming the film in the longitudinal and transverse directions, or in the longitudinal and transverse directions. A method of sequential biaxial stretching in the longitudinal direction, a method of simultaneous biaxial stretching in the longitudinal direction and the transverse direction, etc. can be employed.

[0046] In the case of fibers, spinning is performed by a known method, for example, usually by melt extrusion at 280 to 300°C, and to a length of 500 to 800 m.
After spinning at a speed of /min, e.g. stretching or false twisting,
Alternatively, a method of heat treatment or the like can be adopted.

A feature of the present invention is that by fusing smaller fine particles that have good affinity with polyester to the surface of additive particles that have poor or insufficient affinity with polyester, the added particles In addition to improving the affinity potential of the polyester, the surface on which the small particles are fused has a conpeitou-like shape, so that the polyester penetrates into the valleys, further improving the affinity due to the anchor effect.

The polyester composition of the present invention has excellent slip properties and excellent affinity between the particles and the polyester, so it can be used to form molded products with various advantages such as good abrasion resistance, and can be used for various purposes. can. Especially slipperiness, abrasion resistance,
Furthermore, it can be preferably used in the film field and textile field, which require transparency.

[0049]

[Examples] The present invention will be explained in more detail below with reference to Examples. In addition, "part" in an Example means a weight part. Further, each characteristic value in the Examples was measured according to the following method.

[0050] (1) Particle size of particles There are the following conditions for particle size measurement.

1) When determining the average particle size, particle size ratio, etc. from powder 2
) When determining the average particle size, particle size ratio, etc. of the particles in the film 1) In the case of powder: Scatter the powder on an electron microscope sample stage so that the individual particles do not overlap as much as possible, and use a gold sputtering device to coat this surface. A thin gold film vapor-deposited layer is formed to a thickness of 20 to 30 mμ, and observed with a scanning electron microscope at a magnification of, for example, 10,000 to 30,000 times.
at least 100 particle long diameters (Dli) at 0;
The minor axis (Dsi) and area circle equivalent (Di) are determined. Then, the average particle size is calculated from these values.

2) In the case of particles in a film A small piece of sample film was fixed on a sample stage for a scanning electron microscope, and sputtered using a sputtering device (JFC-1 manufactured by JEOL Ltd.).
The surface of the film is subjected to ion etching using a 100-type ion etching apparatus under the following conditions.

The conditions were as follows: The sample was placed in a bell jar, the degree of vacuum was increased to about 10-3 Torr, and the voltage was 0.
．． Ion etching is performed for about 10 minutes at 25 kV and a current of 12.5 mA. Furthermore, using the same equipment, gold sputtering was applied to the film surface, and a scanning electron microscope was used to perform gold sputtering on the film surface.
Observe at 00 to 30,000 times magnification and use the Japanese regulator (
The major axis (Dli), minor axis (Dsi), and area circle equivalent diameter (Di) of at least 100 particles are determined using Luzex 500 manufactured by Co., Ltd. Then, the average particle size is calculated from those values. (2) Affinity Expose the area around the particles in the film (surface) according to the method (1)-2) above, measure the major diameter of at least 50 particles and the major diameter of the void, and calculate the following formula: void ratio = major diameter of the void. / Find the number average value of the void ratio expressed by the major axis of the particles.

[0054] This numerical average value is displayed based on the following criteria.

[0055] Grade 1: 1≦void ratio <1.5 (that is, voids do not exist or are very small) Grade 2: 1.5≦Void ratio <2.0 Grade 3: 2.0≦Void ratio <3 .0 Grade 4: 3.0≦Void ratio<4.0 (3) Abrasion resistance The abrasion resistance of the running surface of the film is evaluated using a 5-stage mini super calendar. The calender is a five-stage calender consisting of nylon rolls and steel rolls, and the processing temperature is 80° C., the linear pressure applied to the film is 200 kg/cm, and the film is run at a speed of 50 m/min. After running the running film for a total length of 6,000 m, the abrasion resistance of the film was evaluated based on the dirt that adhered to the top roller of the calendar.

<4-level evaluation> ◎ Nylon roll is not soiled at all ○ Nylon roll is hardly soiled × Nylon roll is soiled × × Nylon roll is extremely soiled (4) Haze (cloudiness) According to JIS-K674, Japan Determine the haze of the film using an integrating sphere HTR meter manufactured by Seimitsu Kogaku Co., Ltd.

[0057]

[Example 1] [Surface treatment of organic polymer particles] Spherical silicone particles 9 produced by hydrolysis and condensation of methyltrimethoxysilane with an average particle size of 0.7 μm
7 parts and 3 parts of cross-linked polystyrene fine particles with an average particle diameter of 0.04 μm were dispersed and mixed using a hybridizer (manufactured by Nara Kikai Co., Ltd.), and the cross-linked polystyrene fine particles were fused to the surface of the silicone particles by mechanical impact. Fixed and coated.

When the surface of the obtained composite particles was observed using a scanning electron microscope, it was observed at a magnification of 50,000 times that the crosslinked polystyrene fine particles were uniformly implanted and fused onto the surface of the silicone particles. . [Addition to polyester] Intrinsic viscosity (orthochlorophenol, 35°C) 0.62
dl/g of polyethylene terephthalate chips and the powder (composite particles) obtained above were mixed to a powder content of 0.2% by weight.
The mixture was blended and kneaded and extruded using a twin screw extruder. At this time, in order to suppress a decrease in intrinsic viscosity, vacuum suction was applied from two extruder nozzles to a pressure of 0.1 to 0.2 Torr. After extrusion, the product was cooled with water and made into chips, and the intrinsic viscosity was 0.60 dl/g. [Manufacture of film] Next, the obtained polyethylene terephthalate composition chips were dried at 180°C, formed into a sheet using a melt extruder, and then stretched at 90°C at a longitudinal stretch ratio of 3.5 times and a transverse stretch ratio of 4.
It was biaxially stretched to 0 times and then heat set to form a film with a thickness of 15 μm.

Table 1 shows the properties of this film. In the obtained film, there were mainly no voids around the particles, and even if there were voids, they were extremely small. The film also had good abrasion resistance and transparency.

[0060]

Comparative Example 1 A film was obtained in the same manner as in Example 1, except that the surfaces of the silicone particles were not fused and coated with crosslinked polystyrene fine particles.

The results are shown in Table 1. The obtained film was poor in both abrasion resistance and haze.

[0062]

[Comparative Example 2] Using the method of Example 1, cross-linked polystyrene fine particles were prepared so that the average particle size was 1/1/1 of the average particle size of silicone.
A film was obtained in the same manner except that No. 4 was used.

The results are shown in Table 1. The obtained film had extremely poor affinity and haze, and was also poor in abrasion resistance and transparency.

[0064]

Example 2 A film was produced in the same manner as in Example 1 except that polyphenyl ester resin particles having an average particle size of 0.65 μm were used instead of silicone particles.

The properties of the film are shown in Table 1, and both abrasion resistance and transparency were good.

[0066]

Comparative Example 3 A film was obtained in the same manner as in Example 2 except that the surface of the polyphenyl ester resin particles was not fused and coated with crosslinked polystyrene fine particles.

The properties of the obtained film are shown in Table 1.
Both abrasion resistance and transparency were poor.

[0068]

[Example 3] Using the method of Example 1, calcium carbonate with an average particle size of 0.8 μm was used instead of silicone particles, and the amount of calcium carbonate added to polyester was 0.2 μm, which was coated with cross-linked polystyrene fine particles. A film was obtained in the same manner except that the weight % was used.

The properties of the film are shown in Table 1, and both abrasion resistance and transparency were extremely good.

[0070]

Comparative Example 4 A film was obtained in the same manner as in Example 1 except that the surface of the calcium carbonate particles was not coated with crosslinked polystyrene fine particles.

[0071] The results are shown in Table 1. The film haze obtained was extremely poor at 15.0%, and the particle size was 3-4%.
There were twice as many voids scattered around, and the affinity was poor.

[0072]

[Example 4] Same procedure as in Example 3 except that barium sulfate with an average particle size of 0.6 μm was used instead of calcium carbonate, and the amount of barium sulfate added to the polyester coated with cross-linked polystyrene fine particles was 3500 ppm. A film was produced by going to

The properties of the film are shown in Table 1, and both abrasion resistance and transparency were good.

[0074]

[Example 5] In the method of Example 3, true spherical silica with an average particle size of 0.7 μm was used instead of calcium carbonate, and the amount of true spherical silica coated with crosslinked polystyrene fine particles added to polyester was 0. A film was obtained in the same manner except that the amount was changed to .2% by weight.

The properties of the film are shown in Table 1, and both abrasion resistance and transparency were extremely good.

[0076]

Example 6 A film was produced in the same manner as in Example 7 except that polyethylene terephthalate was changed to polyethylene-2,6-naphthalate.

The properties of the film are shown in Table 1, and both abrasion resistance and transparency were good.

[0078]

[Example 7] [Synthesis of spherical titanium dioxide] A titanium tetraethoxide aerosol was subjected to a hydrolysis/dehydration reaction in a nitrogen gas atmosphere containing saturated vapor of ethylene glycol and water to obtain truly spherical titanium dioxide. This titanium dioxide had an average particle size of 0.6 μm, a relative standard deviation of diameters of 0.5, and was spherical with a uniform size. [Production of film] Using the method of Example 3, the above spherical titanium dioxide was used instead of calcium carbonate, and the amount of the spherical titanium dioxide coated with cross-linked polystyrene fine particles added to the polyester was reduced to 0.
．． A film was produced in the same manner except that the amount was 2% by weight.

The properties of the film are shown in Table 1, and both abrasion resistance and transparency were good.

[0080]

Comparative Example 5 A film was produced in the same manner as in Comparative Example 4 except that ordinary titanium dioxide was used instead of calcium carbonate.

The properties of the obtained film are shown in Table 1.
Both abrasion resistance and transparency were poor.

[0082]

[Table 1]

[0083]

According to the present invention, it is possible to provide a polyester composition that can form molded articles with small voids and excellent slip properties, especially abrasion resistance.

Claims (3)

[Claims] Claim 1: The surface of organic polymer particles or inert inorganic particles with an average particle diameter of 0.05 to 5 μm is fused and coated with crosslinked polystyrene fine particles whose ratio of the average particle diameter to the average particle diameter is 1/5 or less. 1. A polyester composition comprising composite particles having 2. Crosslinked polystyrene fine particles have an average particle diameter of 0.
2. The polyester composition according to claim 1, wherein the polyester composition has a particle diameter of 0.005 to 1 .mu.m, and the amount of fused coating is 0.002 to 10% by weight based on the organic polymer particles or inert inorganic particles. 3. The polyester composition according to claim 1, wherein the content of the composite particles is 0.005 to 5% by weight based on the polyester.