JPH0192265A - Thermoplastic polyester composition - Google Patents

Abstract

PURPOSE:To obtain a composition, having excellent slipperiness and abrasion resistance and especially suitable as magnetic tapes, by homogeneously dispersing calcium carbonate particles having calcium phosphate formed on at least part of the surfaces in a thermoplastic polyester. CONSTITUTION:A thermoplastic polyester composition obtained by homogeneously dispersing (A) calcium carbonate particles prepared by mixing, e.g., calcium carbonate particles (0.01-5mum average particle diameter when a molded product is a film or fiber) with ethylene glycol, etc., reacting the resultant slurry with dilute phosphoric acid (e.g., orthophosphoric acid) while stirring the resultant slurry and forming calcium phosphate in an amount of preferably 0.01-100pts. wt., more preferably 0.1-30pts.wt. based on 100pts.wt. calcium carbonate particles in (B) a thermoplastic polyester [preferably consisting essentially of polyethylene terephthalate (PETP)]. The component (A) is preferably added before ester interchange reaction of the component (B), etc.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a thermoplastic polyester composition, and more specifically to a thermoplastic polyester composition in which surface-modified calcium carbonate particles are uniformly finely dispersed in a thermoplastic polyester. The present invention relates to a thermoplastic polyester composition suitable for making films or fibers with excellent slip properties and abrasion resistance.

[Prior Art] Thermoplastic polyesters, such as polyethylene terephthalate, generally have excellent mechanical and chemical properties.
Widely used as molded products such as films and fibers.

However, when this polyester is processed into a molded article, there is a problem in that productivity is reduced due to insufficient slipperiness. As a method to improve such problems, a method has been conventionally used in which inert particles are dispersed in polyester to impart irregularities to the surface of the molded product. For example, JP-A-49-130448 proposes calcium carbonate surface-treated with a bis fatty acid amide compound and a fatty acid ester compound, and JP-A-52-78953 proposes a combination of calcium carbonate and other particles. Although these methods are effective in solving the problem of slipperiness, they cannot provide a satisfactory level of abrasion resistance when molded products are produced.

If the abrasion resistance of a molded product, such as a film for magnetic tape, is low, abrasion particles of the film are likely to be generated during the manufacturing process of the magnetic tape, and coating handling may occur during the process of applying the magnetic layer, resulting in damage to the magnetic recording. Causes throwing (drop out), etc. Furthermore, when magnetic tape is used, it is often run in contact with recording and playback equipment, etc., so abrasion powder generated during contact adheres to the magnetic material, making it difficult to handle magnetic recording (drops, etc.) during recording and playback. out). That is, magnetic tape films must have slipperiness and abrasion resistance both during the magnetic tape manufacturing process and when used as a magnetic tape. As a method for improving wear resistance, for example,
No. 5 proposes a method using calcium carbonate particles with a defined heat loss rate, and JP-A-60-71632@ proposes surface treatment of calcium carbonate particles with a carboxylic acid compound. However, even if these methods are adopted, the affinity between calcium carbonate particles and polyester is still insufficient, and the abrasion resistance is still insufficient.

[Problems to be Solved by the Invention] The purpose of the present invention is to eliminate the above-mentioned drawbacks of the prior art, and in particular to improve the affinity between calcium carbonate particles and thermoplastic polyester, thereby improving slipperiness and wear resistance. The object of the present invention is to obtain a polyester composition from which films and fibers with excellent properties can be produced.

[Means for Solving the Problems] The above-mentioned objects of the present invention can be achieved by a thermoplastic polyester composition containing calcium carbonate particles having calcium phosphate formed on a part or all of their surfaces. .

Calcium phosphate in the present invention refers to poly(n+2)
- Phosphoric acid (P, 03o, 1) (where n-2
The main ingredients are salts of ~6) and calcium.
The calcium phosphate is made into 1σ by, for example, applying dilute phosphoric acid to a glycol slurry of calcium carbonate particles while stirring. The calcium phosphate may be a single component or a mixed component, and a particularly preferred calcium phosphate is an amorphous calcium phosphate that shows no diffraction pattern in X-ray diffraction.

Further, in the present invention, calcium phosphate is formed on at least a part or the entire surface of the calcium carbonate particles,
It is necessary to increase the affinity of polyester.

The presence of calcium phosphate on at least a portion of the surface of the calcium carbonate particles can be confirmed by stirring 1 g of the particles (A) and 0.359 g of hydrogen chloride in 1 Ω distilled water for 10 minutes to 3 Ω at room temperature, and then using the usual method. Particles (B) obtained by separating the solid part and liquid part in a furnace and drying the solid part.
This can be confirmed by detecting a peak attributed to phosphate in the 1000 to 1200 rm-1 region in the diffuse reflection infrared absorption difference spectrum ((A>-(B)) of the particle (A>-(B)). Particles (A>
On the other hand, the ratio of phosphorus element/calcium element in particle (B) is significantly lowered, which also indicates that phosphorus compounds are unevenly distributed on the particle surface. The amount of calcium phosphate is preferably 0.01 to 100 parts by weight, more preferably 0.01 to 100 parts by weight, per 100 parts of calcium carbonate particles.
The amount is 1 to 30 parts by weight, preferably 0.5 to 10 parts by weight.

When the amount of calcium phosphate is less than 0.01 parts by weight per 100 parts by weight of calcium carbonate particles, it is difficult to obtain a sufficient effect on wear resistance. - On the other hand, if it is added during the polycondensation reaction of thermoplastic polyester when it exceeds 100 parts by weight,
This slows down the reactivity and prolongs the polymerization time. The calcium carbonate particles used in the present invention may be either heavy calcium carbonate obtained by crushing natural limestone or synthetic precipitated calcium carbonate. The average particle diameter of the calcium carbonate particles can be arbitrarily selected depending on the purpose of the molded product made from the thermoplastic polyester composition, but when used for films or fibers, it is preferably 0.01-5. Otim, more preferably 0.1 to 3.0 μm is used.

If the average particle diameter of the calcium carbonate particles is less than 0.01 μm, the molded product will not have sufficient slipperiness;
Exceeding this is not preferable because coarse protrusions will occur on the molded product. Note that the average particle diameter is the equivalent method diameter of particles at 50% of all particles measured by a conventional sedimentation method.

The polyester used in the present invention is produced by a polycondensation reaction using a difunctional component such as an aromatic dicarboxylic acid or its dialkyl ester and a glycol component as raw materials. Among these, those mainly composed of polyethylene terephthalate are particularly preferred. This polyester mainly composed of polyethylene terephthalate may be a homopolyester or a] polyester,
Examples of copolymerization components include dicarboxylic acid components such as adipic acid, sebacic acid, phthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylic acid, and 5-sodium sulfoisophthalic acid, and polyester components such as trimellitic acid and pyromellitic acid. carboxylic acid components, oxycarboxylic acid components such as p-oxyethoxybenzoic acid, and tetramethylene glycol, hexamethylene glycol, diethylene glycol, propylene glycol, neopentyl glycol, polyoxyalkylene glycol, p-xylylene glycol, 1
Examples include diol components such as 4-cyclohexane dimetatool and 5-sodium sulforesorcin. Note that the addition time for incorporating calcium carbonate particles into the thermoplastic polyester may be arbitrary, but it is preferably before the transesterification reaction or from before the esterification reaction to before the polycondensation reaction.

[Examples] Next, the present invention will be specifically explained using Examples and Comparative Examples.

The abrasion resistance was evaluated by rubbing a tape-like roll made of a polyester composition with narrow slits against a guide roll made of stainless steel L5US-304 at a constant tension at high speed for a long time, and then evaluating the amount of white powder generated on the guide roll surface. Ranked as follows.

A@・・・・・・No white powder generation at all Class B...
..... Grade 0 with white powder generation ..... Out of those with a large amount of white powder generation, grade A was considered to be passed.

The static friction coefficient was measured by the ΔSTM-D-1894B method, and the film surface roughness was measured using a Surfcom surface roughness meter according to JISBO601, with a needle diameter of 2 μm and a load of 70 mFJ.
The center line average roughness (Ra) measured under the conditions of a measurement reference length of 0.25 m and a cutoff of 0.08 m was adopted. In addition, [η] in the examples is phenol:tetrachloroethane=1
: Intrinsic viscosity determined at 30°C in a mixed solvent of 1 (weight ratio).

Example 1 Synthetic calcium carbonate particles type 8 omega part having an average particle diameter of 0.8 μm, ethylene glycol, and 92 parts by weight were mixed and processed with a sand grinder to obtain 100 parts by weight of slurry. Next, add 0.34 parts by weight of orthophosphoric acid to 10 parts by weight of ethylene glycol.
A phosphoric acid solution was prepared and mixed with 100 parts by weight of the ethylene glycol slurry of the synthetic calcium carbonate.

The mixed slurry was heated to 100°C and stirred for 3 hours.

This slurry was centrifuged to isolate calcium carbonate particles. As described in the text, the surface of this calcium carbonate was eroded with dilute hydrochloric acid, separated into furnaces, and then the difference spectrum was measured by diffuse reflection infrared absorption method. The results are shown in FIG. Figure 1 shows 10
A peak of phosphate group is seen at 00 to 1200 cm-',
It was confirmed that calcium phosphate (Ca 3 (PO4) 2 ) was formed on the surface of calcium carbonate particles.

For reference, Figure 2 shows sample 1ca3 manufactured by Wako Tsumugi Pharmaceutical Co., Ltd.
PO4)2 diffuse reflection infrared absorption spectra are shown.

Note that no crystalline material was observed by X-ray diffraction. Furthermore, when calculating the amount of calcium phosphate by converting elemental phosphorus into calcium phosphate from fluorescent X-ray analysis, it is 6.5 parts by weight per 100 parts by weight of calcium carbonate particles before treatment with dilute hydrochloric acid, and 0.8 parts after treatment. Ta. 100 parts by weight of Hakata dimethyl terephthalate, 62 parts by weight of ethylene glycol, and 0.06 parts by weight of magnesium acetate were added to perform a transesterification reaction, and 12 parts by weight of the slurry prepared earlier and 0.03 parts by weight of antimony oxide were added. , polycondensation was performed to obtain a polyethylene terephthalate composition with [η]=0.621. The polyethylene terephthalate composition obtained here was melt-extruded at 290°C to obtain an unstretched film. This was roughly stretched at 90°C to 3 times the length in the longitudinal and transverse directions, and then heat treated at 220'C for 10 seconds to give a thickness of 1.
A 5 μm film was obtained. The film obtained here was dissolved in a 1:1 (weight ratio) mixed solvent of phenol and tetrachloroethane and centrifuged to isolate calcium carbonate particles.

When the difference spectrum was measured using the diffuse reflection infrared absorption method using the same method as shown above, peaks similar to those in Figure 1 were obtained.
Fluorescent X-ray analysis showed that the amount of calcium phosphate was 6.5 parts per 100 parts by weight of calcium carbonate before treatment with dilute hydrochloric acid.
After treatment, it was 0°8 parts. This film has a Ra 0
．． ○15, the static friction coefficient was 0.82, and when the wear resistance was evaluated, it was graded A.

Example 2 8 parts by weight of synthetic calcium carbonate particles having an average particle size of 0.8 μm and 92 parts by weight of ethylene glycol were mixed and processed with a sand grinder to obtain 100 parts by weight of slurry. Next, orthophosphoric acid o.

1 part by weight was dissolved in 1.5 parts by weight of ethylene glycol to prepare an orthophosphoric acid solution, which was mixed with 9100 parts by weight of the synthetic calcium carbonate salt described above.

The mixed slurry was heated to 100'C and stirred for 3 hours. The amount of calcium phosphate formed on the calcium carbonate particles in this slurry was measured in the same manner as in Example 1, and was found to be 0.18 parts by weight per 100 parts by weight of the calcium carbonate particles. Then, by performing the same operation as in Example 1, [η]=0.
620, a polyethylene terephthalate film having a thickness of 15 μm was obtained. The film obtained here was treated in the same manner as in Example 1, the particles in the film were isolated, and the difference spectrum was measured in the same manner as in Example 1, and the formation of calcium phosphate was confirmed.

The amount of calcium phosphate formed in the calcium carbonate particles in the film was measured in the same manner as in Example 1, and was found to be 0.18 parts by weight before treatment with dilute hydrochloric acid and 0.4 parts after treatment, per 100 parts by weight of calcium carbonate particles. became. This film had an RaO of 018 and a coefficient of static friction of 0.82, and was evaluated for wear resistance and found to be Class A.

Comparative Example 1 8 parts by weight of synthetic calcium carbonate particles with an average particle size of 0.8 μm, 92 parts by weight of ethylene glycol, and 0.4 parts by weight of sodium pyrophosphate decahydrate were mixed, processed with a sand grinder, and heated at 100° got a slurry of the department. On the other hand, 100" Jffi parts of dimethyl terephthalate, 62 parts by weight of ethylene glycol and 0.06 parts by weight of magnesium oxide were added to carry out a transesterification reaction, and 2 parts by weight of the slurry prepared earlier and 0.03 parts of heavy duty antimony oxide were added. In addition, polycondensation was carried out to obtain a polyethylene terephthalate composition with [η] = 0°619.The polyethylene terephthalate composition obtained by increasing the temperature by 1 was melt-extruded at 290°C to obtain an unstretched film. The film was stretched 3 times in the longitudinal and transverse directions at 90'C and heat-treated at 220°C for 10 seconds to obtain a film with a thickness of 15 μm.

This film has a Ra O, 018 and a static friction coefficient of 0.8.
0, and when the wear resistance was evaluated, it was rated B@.

Comparative Example 2 8 parts by weight of synthetic calcium carbonate particles having an average particle diameter of 0.8 μm and 92 parts by weight of ethylene glycol were mixed and processed with a sand grinder to obtain a 100-bisphere type O slurry. Next, 0.01 parts by weight of orthophosphoric acid was added to 1.0 parts by weight of ethylene glycol.
5 parts were dissolved in 1 part to prepare a phosphoric acid solution, which was mixed with 100'JXm parts of the synthetic calcium carbonate slurry. The mixed slurry was heated to 60°C and stirred for 2 hours. The amount of calcium phosphate formed on the calcium carbonate particles in this slurry was measured in the same manner as in Example 1 and was found to be less than 0.01 parts by weight per 100 small parts of the calcium carbonate particles.

After that, the example and 171 were operated once [ηJ=0.62
A polyethylene terephthalate film having a thickness of 0.0 and 15 μm was obtained. The film obtained here was treated in the same manner as in Example 1, the particles in the film were isolated, and the difference spectrum was measured in the same manner as in Example 1, and the formation of calcium phosphate was confirmed.

The amount of calcium phosphate formed in calcium carbonate in the film was measured in the same manner as in Example 1, and was found to be 0.0 parts by weight per 100 parts by weight of calcium carbonate before treatment with dilute hydrochloric acid.
The amount was less than 1 part by weight.

This film had an RaO of 017, a static friction coefficient of 0°83, and a wear resistance of grade 0.

Comparative Example 3 Eight parts of tribasic calcium phosphate having an average particle diameter of 0.3 μm and 92 parts by weight of ethylene glycol were mixed and processed with a sand grinder to obtain a 100-weight hanging type O slurry. On the other hand, 100 parts by weight of dimethyl terephthalate, 62 parts by weight of ethylene glycol and 0.06 parts by weight of magnesium acetate were added to carry out a transesterification reaction, and 2 parts by weight of the previously prepared slurry and 0.03 parts by weight of antimony trioxide were added. was added to polycondensate the polyethylene terephthalate composition [f)] = 0.615 to 19. The polyethylene terephthalate composition obtained here was melt-extruded at 290°C to form an unstretched film. This was roughly stretched 3 times in the longitudinal and transverse directions at 90° C. and heat treated at 220° C. for 10 seconds to obtain a film with a thickness of 15 μm. This film had an Ra of 0.005 and a coefficient of static friction of 1.05, and when evaluated for wear resistance, it was grade 0.

The results of Examples 1 and 2 and Comparative Examples 1 to 3 are summarized in Table 1.

(Left below) [Advantageous Effects of the Invention 1] Since the calcium carbonate particles in the polyester of the present invention have good affinity with polyester, the abrasion resistance of the polyester composition is good.

Therefore, although the polyester composition of the present invention is effective in making polyester fibers, films, and other molded articles, it can be particularly preferably used in magnetic tapes that are used repeatedly by friction.

[Brief explanation of the drawing]

Figure 1 shows the diffuse reflection infrared absorption spectra of calci carbonate cum particles before and after treatment with dilute hydrochloric acid. Figure 2 shows the diffuse reflection infrared absorption spectra of tricalcium phosphate (Ca 3 (PO4) 2 > diffuse reflection infrared absorption spectra).

Claims (1)

[Claims] A thermoplastic polyester composition comprising calcium carbonate particles having calcium phosphate formed on part or all of their surfaces.