JP3766959B2 - Coated polytrimethylene terephthalate products - Google Patents

Description

The present invention relates to a coated polytrimethylene terephthalate product characterized by coating a hard film of silicon dioxide.
More specifically, the present invention provides excellent impact resistance, wear resistance, scratch resistance, affinity, heat resistance, environmental performance by coating a carbon-based film on polytrimethylene terephthalate resin having excellent environmental load characteristics. In other words, the obtained packaging container, sliding member and the like exhibit excellent characteristics.

  Plastic products have been developed in consideration of collection / recycling, easy incineration, weight reduction, and dehalogenation due to increasing environmental problems. The waste disposal problem is even more serious. Under such circumstances, researches such as PET bottle recycling technology and easy incineration of polyolefins have been made, and one of them has also appeared a means of degrading plastics called biodegradable plastics by microorganisms. However, in reality, biodegradable plastics have one aspect of solving waste disposal problems, but in order to replace them with current general-purpose plastics, mechanical strength, surface hardness, workability, etc. There are still many problems in life cycle, safety and cost because performance is not satisfied.

  In Europe in 1990, shampoo bottles using “Biopol” were shipped as samples, and biodegradable plastics were highlighted. After that, products using various biodegradable plastics were prototyped. Currently, the production of biodegradable plastics is being studied not only by microbial synthesis such as Bipol but also by natural polymers and chemical synthesis, and the method of chemically synthesizing from chemical raw materials is easy to apply the conventional technology. Most promising. Among them, polytrimethylene terephthalate, which is excellent in transparency and has physical properties similar to polyethylene terephthalate (PET), is made from 1,3-propanediol (POD) as a raw material and is a resin with excellent biodegradability. It is known. In chemical synthesis, polytrimethylene terephthalate has a problem that its production cost is high compared to PET using ethylene glycol as a raw material because POD is expensive. However, since POD, which is a raw material in the United States, has invented a single microorganism that converts sugar to glycerin by genetic modification and further converts it to 1,3-propanediol (POD), polytrimethylene terephthalate can be produced at low cost. It became clear that it could be manufactured and began to be put into practical use.

  However, the prior art disclosed with respect to the conventional polytrimethylene terephthalate resin has many applications relating to fibers. For example, in Japanese Patent Laid-Open No. 11-12824, the lining is constituted by an invention relating to a lining using polytrimethylene phthalate fibers It is disclosed that the use of polytrimethylene phthalate fibers for the warp and / or the weft can significantly improve the seam allowance / creaseability and the recovery property of the firmly attached heel. Japanese Patent Laid-Open No. 2001-115344 discloses that a stretch function and a feeling of spanization can be achieved by a special composite crimped yarn using two or more kinds of compound crimped yarns containing polytrimethylene terephthalate. As described above, the use of PTT has been preceded for fibers, but it has great potential as a molding material. PET has a slow crystallization rate and poor injection moldability, whereas PTT has excellent performance close to that of PET and has moldability comparable to polybutylene terephthalate (PBT). Furthermore, the glass fiber reinforcing effect is most excellent as compared with other crystalline resins such as PET, PBT, and nylon.

  On the other hand, regarding a surface modification technique for forming a carbon film on a resin, Japanese Patent Application Laid-Open No. 6-88209 discloses a plastic substrate having a melting point of 150 ° C. or less and coated with a diamond-like carbon film. . Japanese Patent Application Laid-Open No. 11-58587 discloses an oxidation film comprising a laminated film in which a diamond-like carbon film having a hydrogen concentration of 50 atomic% or less and an oxygen concentration of 2 to 20 atomic% is formed on at least one surface of a plastic. A protective wrapping film is disclosed. Furthermore, after a silicon dioxide film is formed on the PET film, a diamond-like carbon (DLC) film is formed by a plasma CVD method so as to embed defects such as cracks, pinholes or crystal grain boundaries existing in the silicon dioxide film. This is disclosed in Japanese Patent Application Laid-Open No. 11-245327.

Regarding the formation of DLC films on plastic containers, JP-A-2001-240034 discloses a polyethylene terephthalate resin (PET) for the purpose of flavor barrier properties and gas barrier properties of volatile organic solvents. Japanese Patent Laid-Open No. 2000-103884 discloses a method for irradiating carbon, titanium, aluminum, tungsten, argon, nitrogen and silicon ions to PET, polycarbonate, and amorphous polyolefin to irradiate them with plastic surfaces. ing.
On the other hand, the film formation of silicon dioxide is carried out using PET bottles as a transparent and gas barrier film, but the PET and the silicon dioxide film can be easily peeled off during recycling. Since the interlayer adhesion of silicon dioxide (SiO2) is not sufficient, it has not been put into practical use.

  Conventional plastics, such as PET, are very often discarded because the recycling of inorganic materials after coating is limited. Since these coated plastics are not decomposed in the soil, there is a problem that the burden on the environment is extremely large. On the other hand, polytrimethylene terephthalate has excellent environmental characteristics, but it has been mainly applied to fibers and the like as described above due to poor mechanical properties, scratch resistance and reactivity. . Therefore, there has been a demand for a utilization technique that can be applied to various mechanical uses, consumer products, recording media, and the like.

As a result of various studies on the surface modification of polytrimethylene terephthalate having good biodegradability, the present inventors have arrived at the present invention.
Basically, the surface of polytrimethylene terephthalate is coated with silicon dioxide, and by having SP2 and SP3 bonds, wear resistance, hardness and reactivity are improved, and excellent environmental characteristics are obtained. It became clear that it did not inhibit.

That is, the present invention is characterized by the following configuration.

(1) A coated polytrimethylene terephthalate product characterized by being a consumer product, an optical material, an abrasive, a protective device, a medical instrument, a packaging container or a sliding member coated with a hard film made of silicon dioxide.
(2) The coated polytrimethylene terephthalate product according to (1) above, wherein the hard film is at least one of amorphous, SP2 bond or SP3 bond.
(3) The coated polytrimethylene terephthalate product according to (1) or (2) above, wherein the silicon dioxide film contains 3 to 40% by volume of hydrogen.
(4) The silicon dioxide film is a single layer selected from at least one selected from Group 4a, 5a, and 6a elements of the periodic table, Si, Al, and carbides of these elements and carbon or a multilayer of two or more layers The coated polytrimethylene terephthalate product according to any one of (1) to (3) above, wherein the coated polytrimethylene terephthalate product is a hard film.

(5) The silicon dioxide in the coating film has a layer having a different SP2 / SP3 ratio at an approximate interface between the polytrimethylene terephthalate and the coating film as compared with the upper part of the coating film ( The coated polytrimethylene terephthalate product according to any one of 1) to (4).
(6) The coated polytrimethylene terephthalate product according to any one of (1) to (5) above, wherein the silicon dioxide film has a thickness of 0.01 μm to 10 μm.

  DLC (diamond like carbon), which is a hard carbon film in the present invention, is coated by ionizing a hydrocarbon gas or solid carbon, and further coating any of a mixed film with a metal to improve adhesion. Therefore, it is preferable. In the case of solid carbon, it is vaporized by direct irradiation with an electron beam, and a voltage is applied to form plasma. Control of amorphous, SP2 bond and SP3 bond is controlled by input energy value, applied voltage, ionization rate or vacuum degree, and the applied voltage may be pulsed. It can also be obtained by simultaneously introducing a hydrocarbon gas such as methane or benzene and hydrogen, and a carbon film containing hydrogen can be obtained. Furthermore, it is preferable because a thick film can be easily obtained by mixing a metal, stress is relieved, and high adhesion is easily obtained.

  On the other hand, silicon dioxide is excellent in transparency, hardness, chemical resistance and gas barrier effect of the film, and the coating of silicon dioxide directly or directly applies an electron beam to a silicon dioxide substrate in an inert gas atmosphere. Vaporization is caused by indirect irradiation, and plasma is generated by a voltage applied thereto. Control of amorphous, SP2 bond and SP3 bond can be controlled by input energy value, applied voltage, ionization rate, vacuum degree, etc. as in the case of carbon, but in the case of silicon dioxide, the thickness of the film There is a drawback in that the flexibility decreases as the amount increases.

  Polytrimethylene terephthalate (PTT), which is biodegradable and excellent in transparency and workability, but inferior in wear resistance, hardness and reactivity, is coated with diamond-like carbon and silicon dioxide having SP2 and SP3 bonds. By performing surface modification, the interlayer adhesion between PTT and these coatings is not only very good, but these properties can be remarkably improved without sacrificing environmental properties by maintaining biodegradability. Therefore, it has become possible to apply to various mechanical uses, consumer products, optical materials, abrasives, protective equipment, medical instruments and the like that have been considered to be unusable.

  The main structural unit of polytrimethylene terephthalate (PPT) in the present invention is composed of a terephthalic acid component and a trimethylene glycol component. That is, although the polymer which is a trimethylene terephthalate unit is pointed out, a small amount, for example, 20 mol% or less, Preferably 5 mol% or less may be knitted | organized with other components. Examples of other components include phthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid and its isomers, adipic acid, sebacic acid, oxycarboxylic acid, ethylene glycol, butanediol, 1,4-cyclohexanedimethanol or Mention may be made of neopentyl glycol. However, the modification degrades the biodegradability and increases the environmental load. Therefore, when biodegradability is intended, the content of the other components is limited.

  In the present invention, the PPT includes other polyesters such as polyethylene terephthalate, polybutylene terephthalate, polycyclohexanedimethylene terephthalate, polyethylene naphthalate, polyethylene or polypropylene, or inert fine particles. For example, one or more metal compounds or carbon black selected from kaolin, talc, magnesium carbonate, calcium carbonate, barium carbonate, calcium sulfate, barium sulfate, calcium phosphate, magnesium phosphate, aluminum oxide, silicon oxide, titanium oxide, etc. You may blend. However, since the biodegradability is lowered, it is desirably 20% by volume or less, preferably 5% by volume or less. Furthermore, you may mix | blend an antistatic agent, a flame retardant, a lubricant, antioxidant, a ultraviolet absorber, a dye content, etc.

The coated polytrimethylene terephthalate of the present invention is first molded into a film having a thickness of 0.01 to 0.8 mm, and then molded into various desired shapes to obtain a molded product of polytrimethylene terephthalate. The obtained molded article is further charged into a vacuum chamber, and the above-described DLC or silicon dioxide film is coated on the surface or inside thereof by a plasma CVD method or a PVD method.
Each coating method has its characteristics, but in plasma CVD method, carbon source gas, for example, methane, ethane, propane, acetylene, benzene, alcohol, etc. are essential, and introduction gas such as hydrogen, argon, xenon is mixed. Then, a voltage is applied in a vacuum of about 1.33 to 0.13 Pa to form plasma, and a film is formed on the surface of the molded product of polytrimethylene terephthalate. In order to form the SP2 / SP3 mixed crystal film, the ratio of the gas species serving as the carbon source is increased and further controlled by the degree of vacuum, the applied voltage, and the gas flow rate.

The coating composition is preferable because the effect of dispersing the stress is exhibited when the SP2 bond is greater than the SP3 bond, but the effect of dispersing the stress is exhibited, and the adhesion with the underlying polytrimethylene terephthalate molded article is improved. Furthermore, in applications where high adhesion is required, it is preferable that at least one selected from the group 4a, 5a, and 6a metals of the periodic table, Si, Al, and carbides of these metals be the underlayer. In addition, by laminating these metals and metal carbides and a carbon film, the compressive residual stress in the carbon film is relaxed, and as a result, a thick film is obtained, which is preferable.
The metal and metal carbide may be formed by vaporizing metal chloride or fluoride and bubbling with argon or the like, and ionizing the introduced gas such as hydride to form a polytrimethylene terephthalate molded article surface. The metal carbide may be formed by mixing the carbon source at the same time.

If the thickness of the coating film is less than 0.01 μm, it does not function as a coating film, and if it is thicker than 10 μm, it tends to peel due to the compressive residual stress of the coating film itself.
The carbon film is preferable because it contains 3 to 40% by volume of hydrogen rather than being formed only from carbon, because smoothness, denseness, and reactivity are excellent.
Coated polytrimethylene terephthalate is preferable for containers and recording media because its environmental properties are particularly required.

  Embodiments of the present invention will be described below based on reference examples and examples, but the present invention is not limited thereto.

[Reference Example 1]
A plastic bottle (container thickness: 300 μm) of PTT was placed in a vacuum vessel of a plasma processing apparatus, and a negative voltage of 1 kV was applied while maintaining the pressure in the vacuum vessel in a mixed gas atmosphere of argon and ethane of 0.55 Pa. However, ethane was ionized and ionized in glow discharge plasma, and surface modification of diamond-like carbon (DLC) could be performed on the surface of the PTT bottle. As a result of measuring the bottle surface by FT-IR, the absorption of 1730 cm ⁻¹ ester, which was observed before the plasma treatment, was not observed after the plasma treatment, and in the surface analysis by ESCA, most of the signals were carbon signals. It was. Moreover, as a result of measuring the surface with a scanning probe microscope (SPM), it was confirmed that a crystal part and an amorphous part coexist. The side of the bottle whose surface was modified was cut out with a cutter knife to make a sample for measuring physical properties, and changes in the physical properties were measured and confirmed for the following items. As a comparative sample, a PTT bottle not subjected to plasma treatment and a PET bottle having the same container thickness were used.
Note that the surface pencil hardness test shows the hardness of a pencil that does not cause dents on the surface of the material on which the DLC film is formed using pencils having different hardnesses ranging from 6B to 6H. In the biodegradability test, measured values were large, medium, and small by BOD measurement according to ASTM test D5271-93, and showed gradually from non-degradable to easily degradable.

[Table 1]
Comparison of physical properties of PTT, surface modified PPT and competitive resin (PET)
Physical properties PTT DLC modified PTT PET
Tensile strength (Mpa) 67.6 66.5 72.5
Flexural modulus (Gpa) 2.76 2.43 3.11
Izod impact strength (J / m) 48 46 37
Mold shrinkage (m / m) 0.020 0.020 0.030
Melting point (° C) 225 225 265
Glass transition point (° C) 45-75 45-76 80
Surface pencil hardness HB 6H 5H
Biodegradability test Large Large Small

  As a result of this test, it was revealed that the DLC-modified PTT bottle was superior to the PET bottle and had improved surface hardness without peeling off the DLC coating in the impact resistance test. Furthermore, it became clear that the PTT bottle with the DLC modified surface retains the biodegradability, which is a major feature of the PTT bottle, and can contribute to environmental pollution after using the bottle by using the DTT modified PTT bottle. It was.

[Reference Example 2]
Using two films (thickness: 500 μm) made of PTT and PET, each is put into a vacuum vessel of a plasma processing apparatus, the pressure inside the vacuum vessel is 0.8 Pa, and argon and methane are 2 to 1 Plasma discharge was performed in a mixed gas atmosphere to form a DLC film. About these two films | membranes, the adhesiveness of a DLC film | membrane and a raw material was confirmed by the Goban eye test and the elixir test.
In addition, the gobang eye test was performed by putting 10 vertical and horizontal incision lines leading to the material at 1 mm intervals in the DLC film that is in close contact with the material, and then sufficiently attaching cello tape (registered trademark, Nichiban Co., Ltd.) on it. The number of 1 mm square DLC coatings remaining on the material when the cellophane tape (same) is peeled off instantaneously is shown.
The elixir test shows the indentation distance of the nozzle where the DLC film peels from the substrate when the film is installed in the apparatus and a nozzle having a spherical tip is pushed in from the back side of the film. Therefore, it indicates that the interlayer adhesion is better as the pushing movement distance is larger.

  Table 2 shows the results of interlayer adhesion test compared with PTT PET.

[Table 2]
Comparison of adhesion between PTT and PET materials and DLC coating
Test material PTT PET
Gobang Eye Test 100 72
Erichsen test (mm) 8.58 4.36
DLC coating surface hardness 6H 6H

[Example 1]
The reaction vessel and reaction conditions of Reference Examples 1 and 2 are adopted, and tetramethylsilane (TMS) and oxygen gas are used. That is, as a result of generating low-temperature plasma in an atmosphere in which the ratio of TMS to oxygen gas is 1: 1 on the polytrimethylene terephthalate substrate, the surface hardness of the polytrimethylene terephthalate is the same as that of the substrate before plasma irradiation. It was significantly larger than that. When the surface of this plasma-treated polytrimethylene terephthalate was analyzed by ESCA, a spectrum of silicon and oxygen was detected, and it was confirmed that a silicon dioxide film was formed on the surface of the PTT film. Further, after removing the surface of this PTT by sputtering with Ar ions to a depth of 10 μm, when the surface was similarly subjected to surface analysis by ESCA, the previously detected Si spectrum was not observed, but the spectra of carbon and oxygen were detected. . From this, it was confirmed that SiO2 formed a film on the surface of PTT.

Claims (1)

A coated polytrimethylene terephthalate product comprising an abrasive, a protective device, a medical device, a packaging container, or a sliding member in which a hard film made of silicon dioxide is coated on the surface of a substrate .