JP2898026B2 - Molded article of styrenic polymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a molded article of a styrenic polymer, and more particularly to a molded article made of a specific material, which is obtained by subjecting a surface thereof to a certain treatment. And a molded product having an improved surface tension.

[Problems to be solved by conventional technology and invention]

Conventionally, molded products such as polyolefins such as polyethylene and polypropylene, atactic polystyrene, polyethylene terephthalate, and the like have been improved in printability and adhesive strength of the laminate with respect to printing on the surface and lamination performed normally. Those with improved tension are known.

However, although these resins have improved surface tension, their applications are limited due to insufficient physical properties of the resins themselves. For example, polyolefin and atactic polystyrene have insufficient heat resistance, and polyethylene terephthalate has problems in water resistance and moisture resistance. Therefore, they cannot be used under a severe environment.

The styrenic polymer having a syndiotactic structure previously proposed by the present inventors is excellent in heat resistance, chemical resistance, water resistance, and electrical insulation. It has excellent mechanical properties and dimensional stability, and is expected to be widely used in fields where the use of the above resins is restricted. (Japanese Patent Application No. 63-3847) This styrenic polymer having a syndiotactic structure is superior in heat resistance, water resistance, moisture resistance, etc. as compared with the above-mentioned conventional resins, but is not melt molded or Molded products such as films and sheets obtained by stretching and the like have low surface tension, and their suitability for printing and laminating is not always satisfactory.

Thus, the present inventors have made intensive studies to develop a molded article having surface properties suitable for printing, lamination, and the like, using a styrenic polymer having excellent properties as a material.

As a result, they have found that a desired molded product can be obtained by subjecting the surface of a molded product made of a styrene-based polymer having a syndiotactic structure to a chemical or physical treatment. The present invention has been completed based on such findings.

[Means for solving the problem]

That is, the present invention comprises a styrenic polymer having a syndiotactic structure or a composition of the polymer, and at least a part of the surface is subjected to a chemical treatment and / or a physical treatment, and the surface tension of the treated part is reduced. An object of the present invention is to provide a molded article of a styrene-based polymer, which is characterized by being at least 35 dyne / cm.

The styrene-based polymer having a syndiotactic structure used in the present invention is a syndiotactic structure having a stereochemical structure, that is, a phenyl group or a substituted phenyl group which is a side chain with respect to a main chain formed from carbon-carbon bonds. Are alternately located in opposite directions, and their tacticity is determined by nuclear magnetic resonance ( ¹³⁾
C-NMR method). Tacticity measured by the ¹³ C-NMR method can be represented by the abundance ratio of a plurality of continuous structural units, for example, a dyad for two, a triad for three, and a pentad for five. However, the styrenic polymer having a syndiotactic structure referred to in the present invention is usually 75% by racemic dyad.
%, Preferably 85% or more, or polystyrene, poly (alkylstyrene), poly (halogenated styrene), poly (alkoxystyrene) having a syndiotacticity of 30% or more, preferably 50% or more in racemic pentad. , Poly (vinyl benzoate), hydrogenated polymers thereof and mixtures thereof, or copolymers containing these structural units. Here, poly (alkylstyrene) includes poly (methylstyrene), poly (ethylstyrene), poly (propylstyrene), poly (butylstyrene), poly (phenylstyrene), poly (vinylnaphthalene), and poly (vinylstyrene). Vinyl (styrene)) and poly (acenaphthylene). Poly (halogenated styrene) includes poly (chlorostyrene),
Examples include poly (bromostyrene) and poly (fluorostyrene). Examples of poly (alkoxystyrene) include poly (methoxystyrene) and poly (ethoxystyrene). Of these, particularly preferred styrene polymers include polystyrene, poly (p-methylstyrene), poly (m-methylstyrene), poly (p-tert-butylstyrene), poly (p-chlorostyrene), and poly (p-chlorostyrene). m-chlorostyrene), poly (p-fluorostyrene), and a copolymer of styrene and p-methylstyrene (JP-A-62-187708).

Further, as the comonomer in the styrenic copolymer, in addition to the styrenic polymer monomer as described above, olefin monomers such as ethylene, propylene, butene, hexene, and octene; diene monomers such as butadiene and isoprene; and cyclic diene monomers. Examples include polar vinyl monomers such as methyl methacrylate, maleic anhydride, and acrylonitrile.

The molecular weight of the styrenic polymer is not particularly limited, but is preferably 10,000 to 3,000,000, more preferably 50,000 to 1,500,000. Where the weight average molecular weight is 10,000
If it is less than 100%, stretching cannot be performed sufficiently. Further, the molecular weight distribution is not limited in its width and may be any of various types. However, the weight average molecular weight (Mw) / number average molecular weight (Mn) is preferably 1.5 or more and 8 or less. In addition,
The styrene-based polymer having a syndiotactic structure has much better heat resistance than a conventional styrene-based polymer having an atactic structure.

Styrene resin having such a syndiotactic structure is, for example, in an inert hydrocarbon solvent or in the absence of a solvent, a titanium compound and a condensation product of water and trialkylaluminum as a catalyst, a styrene monomer (A monomer corresponding to the styrenic polymer) can be produced (JP-A-62-187708). Further, poly (halogenated alkylstyrene) can be obtained by the method described in JP-A-1-46912, and these hydrogenated polymers can be obtained by the method described in JP-A-1-178505.

The material used in the present invention is basically composed of the above-mentioned styrene-based polymer, and other resins, rubber, inorganic fine particles, antioxidant,
It may be composed of a composition to which a nucleating agent, a plasticizer, a compatibilizer, a coloring agent, an antistatic agent and the like are added.

The inorganic fine particles that can be suitably used here include IA group,
IIA, IVA, VIA, VIIA, VIII, IB, IIB, I
Oxides, hydroxides, sulfides, nitrides, halides, carbonates, acetates, phosphates, phosphites, organic carboxylates, silicates, titanates of Group IIB and IVB elements, There are borates and their hydrated compounds, composite compounds centered on them, and natural mineral particles. Specifically, compounds of Group IA elements such as lithium fluoride, borax (sodium borate hydrate), magnesium carbonate, magnesium phosphate, magnesium oxide (magnesia), magnesium chloride, magnesium acetate, magnesium fluoride, magnesium titanate, silicate Magnesium, magnesium silicate hydrate (talc),
Calcium carbonate, calcium phosphate, calcium phosphite,
Calcium sulfate (gypsum), calcium acetate, calcium terephthalate, calcium hydroxide, calcium silicate, calcium fluoride, calcium titanate, strontium titanate, barium carbonate, barium phosphate, barium sulfate,
Group IIA element compounds such as barium phosphite, IVA such as titanium dioxide (titania), titanium monoxide, titanium nitride, zirconium dioxide (zirconia), zirconium monoxide
Group element compounds, molybdenum dioxide, molybdenum trioxide,
Group VIA element compounds such as molybdenum sulfide, manganese chloride,
Group VII A element compounds such as manganese acetate, cobalt chloride,
Group VIII element compounds such as cobalt acetate, and I such as cuprous iodide
Group B element compounds, Group II B element compounds such as zinc oxide and zinc acetate, and Group III B element compounds such as aluminum oxide (alumina), aluminum hydroxide, aluminum fluoride, and aluminosilicate (alumina silicate, kaolin, kaolinite) And group IVB element compounds such as silicon oxide (silica, silica gel), graphite, carbon, graphite, and glass; and particles of natural minerals such as kernalite, kainite, mica (mica, kinmo), and virose ore. The average particle size of the inorganic fine particles is not particularly limited, but is preferably 0.
It is from 0.01 to 100 μm, more preferably from 0.01 to 3 μm, and its content in the composition is from 0.001 to 3% by weight, preferably from 0.001 to 1% by weight.

The above-mentioned inorganic fine particles are an effective component in improving the slipperiness of the surface of the molded body, but fine particles of other types or other particle sizes, inorganic fillers, or the like, as long as the object of the present invention is not hindered. May be included.

The above-mentioned inorganic fine particles are contained in a final molded product, that is, a film, a sheet, or the like, but the method of containing the inorganic fine particles is not limited. For example, a method of adding or precipitating the styrene-based monomer in an arbitrary step during the polymerization and a method of adding the styrene-based monomer in an arbitrary step of melt-extrusion may be mentioned.

On the other hand, there are various other resins that can be used together with the above-mentioned styrene-based polymer having a syndiotactic structure, and examples thereof include an atactic styrene-based polymer and an isotactic styrene-based polymer. Copolymers, styrene-maleic anhydride copolymers, polyphenylene ethers, etc. are easily compatible with the above-mentioned syndiotactic styrene-based polymer, and are used to prepare preforms for stretching (raw sheets, films, etc.). Is effective in controlling the crystallization of the film, the subsequent stretchability is improved, the stretching conditions can be easily controlled, and a film having excellent mechanical properties can be obtained. Among them, when a styrenic polymer having an atactic structure and / or an isotactic structure is contained, a styrene-based polymer having a syndiotactic structure is preferably used. The content ratio of these compatible resin components may be 70 to 1% by weight, particularly preferably 50 to 2% by weight. Here, when the content ratio of the compatible resin component is more than 70% by weight, heat resistance and the like, which are advantages of the styrene-based polymer having a syndiotactic structure, are not preferable. Examples of the incompatible resin include polyolefins such as polyethylene, polypropylene, polybutene and polypentene; polyesters such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate; nylon-6 and nylon.
Polyamides such as 6,6, polythioethers such as polyphenylene sulfide, polycarbonate, polyarylate,
Polysulfone, polyether ether ketone, polyether sulfone, polyimide, vinyl halide polymers such as Teflon, acrylic polymers such as polymethyl methacrylate, polyvinyl alcohol, etc. And a crosslinked resin containing the above-mentioned compatible resin. Since these resins are incompatible with the syndiotactic styrene polymer of the present invention, if they are contained in small amounts, they can be dispersed like islands in the syndiotactic styrene polymer and stretched. It is effective to give a good gloss later and to improve the slipperiness of the surface. The content ratio of these incompatible resin components is preferably 50 to 2% by weight for the purpose of gloss, and 0.001 to 5% by weight for the purpose of controlling surface properties. When the temperature at which the product is used is high, it is preferable to use a heat-resistant resin.

The molded article of the present invention is obtained by molding the above-mentioned material, and the form is not particularly limited. Specifically, it contains at least one layer composed of the above-mentioned styrene-based polymer or the composition, and after being heated and melted, is extruded into a planar, linear, cylindrical or the like with at least one or more layers. A cooled, solidified sheet, film, or fibrous molded article, a molded article obtained by stretching the molded article in at least one direction, or a composite (laminated film, Woven fabric).

In the present invention, the surface (part or all) of such a molded body is subjected to a chemical surface treatment and / or a physical surface treatment, and the surface tension of the surface treated portion of the molded body is reduced to 35 dyne / c.
The feature is that it is set to m or more. The chemical and physical surface treatment performed here is to reduce the surface tension of the compact by 35dy after the surface treatment.
As long as the processing can be performed at ne / cm or more, various methods can be used without particular limitation. Specifically, the following are mentioned.

First, as a chemical treatment, there is mainly a wet treatment. For example, a molded body is immersed in various chemicals, a target functional group, a carbonyl group in the present invention is introduced to the surface, and a porous surface is formed by an etching effect. Chemical treatment to form the structure,
Coating agent treatment for forming a surface layer by immersing the molded body in a silyl peroxide solution containing a silane-based, titanium-based or chromium-based coupling agent, monomer / polymer coating for coating any monomer or polymer on the molded body surface Steam treatment, in which the vapor of various compounds is applied to the surface of the molded article, the surface is etched by the vapor, and the vapor component is introduced into the surface treatment portion by reacting the component of the vapor with the surface of the molded article. Examples thereof include a surface grafting treatment in which a compound having an oxygen-containing functional group is graft-polymerized, and an electrochemical treatment in which a molded article is immersed in an electrolytic solution to reduce the surface of the molded article.

When such a chemical treatment is performed, since the styrenic polymer used in the present invention has excellent solvent resistance, it is difficult to use an organic solvent having a solubility parameter of 7 to 12 (cal / cm ² ) ^1/2 , Inorganic (aqueous) solutions that can be used with tic polystyrene, as well as gases, are suitably used.

The physical treatment is mainly a dry treatment. For example, a carbonyl group is applied to the surface of the molded body by irradiating the surface of the molded body with ultraviolet rays to form a carbonyl group on the surface, an ultraviolet irradiation treatment, a blow discharge, and a corona discharge. Processing, plasma polymerization processing to form a polymer film on the surface of the molded body in a carrier gas in the plasma state, ion beam processing to accelerate the ions and roughen the surface to the surface of the molded body, mechanochemical Examples include mechanical treatment for effecting surface activation and surface roughening by effect, frame treatment for oxidizing the surface by oxidizing flame, and ozone treatment for blowing high concentration ozone between films immediately before lamination.

Here, in the case of physical treatment, the styrene-based polymer of the present invention is excellent in heat resistance, so that it can be treated at a relatively high temperature, for example, a glass transition temperature higher than the glass transition temperature which was impossible with conventional atactic polystyrene. Effective treatment can be performed at a temperature.

Therefore, an effective surface treatment can be performed in a shorter time than in the past, and the resulting molded article has a uniform and sufficient surface treatment over a large area. The uniformity of the surface treatment is a very important factor in the subsequent processing (printing, lamination, etc.).

Among these methods, methods such as ultraviolet irradiation treatment, plasma treatment, flame treatment, and ozone treatment are particularly preferable.

In the present invention, the surface of the molded body, by performing one or more of the above treatments in combination, or not limited to the above treatment method, by performing other methods, the surface tension is 35 dyne / cm or more , Preferably 37dyne / cm
The above-mentioned molded body is obtained. Here, the surface tension of the compact is 35dy
If it is less than ne / cm, the wettability of the surface is inferior, the paste of the printing ink is insufficient, and the adhesive strength is lowered, which is not preferable.

Incidentally, the surface tension in the present invention according to JIS K6768,
It was measured under the conditions of 23 ° C. and 50% RH (relative humidity) using a surface wetting reagent.

The molded article of the present invention thus obtained is used for various purposes either alone or by laminating it with another resin or the like.

〔Example〕

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples.

Production Example 1 (Production of styrene polymer) (1) made of glass having an inner volume of 500ml was prepared argon substitution of contact product of trimethylaluminum with water, copper sulfate pentahydrate (CuSO ₄ · 5H ₂ O) 17.8 g (71 mmol), 200 ml of toluene and 24 ml (250 mmol) of trimethylaluminum were added and reacted at 40 ° C. for 8 hours. Thereafter, toluene was further distilled off from the solution obtained by removing the solid portion under reduced pressure at room temperature to obtain 6.7 g of a contact product. The molecular weight of the contact purified product was 610 as measured by freezing point depression method.

(2) Production of styrene-based polymer In a reaction vessel having an inner volume of 2 were placed purified styrene 1, 5 mmol of the contact product obtained in (1) above as aluminum atoms, 5 mmol of triisobutylaluminum, and pentamethylcyclopentane. A polymerization reaction was carried out at 90 ° C. for 5 hours using 0.025 mmol of dienyl titanium trimethoxide. After completion of the reaction, the product was decomposed with a methanol solution of sodium hydroxide to decompose the catalyst component, washed repeatedly with methanol, and dried to obtain 308 g of a polymer. The weight average molecular weight of this polymer measured by gel permeation chromatography at 130 ° C. using 1,2,4-triclobenzene as a solvent was 389,000 weight average molecular weight / number average molecular weight was 2.6.
Was 4. Further, the polymer was confirmed to be a polystyrene having a syndiotactic structure by melting point and ¹³ C-NMR measurements.

Example 1 The polystyrene produced in Production Example 1 was extruded at 320 ° C. to obtain a sheet-shaped molded body. The crystallinity of this sheet-like molded product was 14% as determined by a differential scanning calorimeter. The sheet was sequentially stretched longitudinally and laterally by a stretch ratio of 3 times to obtain a biaxially stretched film having a thickness of 15 μm. Further, heat treatment was performed at 250 ° C.

The obtained film was subjected to a corona treatment using a corona treatment device (HFS-203, manufactured by Kasuga Electric) under a treatment density condition of 28 W / m ² · min.

The surface tension of the corona-treated polystyrene biaxially stretched film was 50 dyne / cm.

This film and a linear low-density polyethylene film (Idemitsu Unilux LS730C, 40 μm, manufactured by Idemitsu Petrochemical Co., Ltd.) were bonded to a two-part adhesive manufactured by Toyo Morton (AD-308).
A, AD-308B) to form a laminate film.

When the peel strength of the produced laminated film was measured, a value of 900 g was obtained, indicating that the adhesive strength was strong. The surface tension was measured in accordance with JIS K6768 using a surface wetting reagent at 23 ° C. and 50% RH, and the peel strength of the adhesive was determined by a T-shaped peeling method under the following conditions.

Peeling strength measurement conditions: sample width 15 mm, pulling speed 3 mm / min Example 2 The biaxially stretched film in Example 1 was used under a nitrogen gas atmosphere in a vacuum of 0.5 Torr using a plasma processing apparatus prototyped by the present inventors. Plasma treatment was performed.

The surface tension of the obtained film is 52 dyne / cm,
When the printing ink (Polymate GT) manufactured by Toyo Ink Co., Ltd. was applied, the printability was excellent without bleeding.
Even after the boil treatment for 0 minutes, there was no peeling with the cellophane tape. Also, this film is
There was almost no thermal deformation even after heating for 0 minutes.

Example 3 Example 2 was carried out in the same manner as in Example 2 except that a polystyrene film having a surface tension of 40 dyne / cmT obtained at a treatment density of 14 W / m ² · min was used. The printability and the peel test after the boil treatment were good.

Comparative Example 1 In the examples, the film was not subjected to corona treatment. The surface tension of this film was 33 dyne / cm, and the same adhesiveness evaluation as in Example 1 was performed.
The weight was 300 g, which was not practically endurable.

Comparative Example 2 The polystyrene produced in Production Example 1 was formed into a sheet having a thickness of 400 μm using a T-die.

The surface tension of this sheet was 34 dyne / cm.
Printability was evaluated in the same manner as described above. As a result,
When the cellophane tape was peeled off on the printed surface after drying, the printed surface was easily peeled off, indicating that the printability was insufficient.

Comparative Example 3 Printing was performed in the same manner as in Example 2 except that a surface-modified biaxially stretched polypropylene film (manufactured by Toray, Triphan S645) was used instead of the stretched polystyrene film in Example 2. And boilability were good. However, when heated to 200 ° C., the film melted.

Comparative Example 4 The same operation as in Example 2 was performed, except that a surface-modified biaxially stretched polyester film (manufactured by Toyobo, ester film E5100) was used in place of the stretched polystyrene film in Example 2. . Although printability and heat resistance at 200 ° C. were good, after boil treatment, the polyester film of the base material became brittle due to hydrolysis and could not withstand use [Effect of the Invention] As described above, the present invention The molded article of the styrene polymer of
The surface tension is improved by surface treatment, in addition to the inherent properties such as heat resistance, chemical resistance, and mechanical strength of the polymer. Therefore, the molded article of the present invention is excellent in printability, boil resistance, and adhesiveness with other molded articles, and can easily produce molded articles such as laminates, sheets, and laminates which are firmly adhered.

Accordingly, the molded article of the present invention is widely and effectively used as a material for various industrial and packaging films and sheets.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // D06M 10/00 D06M 10/00 15/00 15/00 C08L 25:00 10/00 15/00 (58) Field surveyed (Int.Cl. ⁶ , DB name) C08J 7/00-7/18 B29C 71/00 C08F 12/08

Claims (6)

(57) [Claims] A styrenic polymer having a syndiotactic structure or a composition of the polymer, wherein at least a part of the surface is subjected to a chemical treatment and / or a physical treatment, and the surface tension of the treated part is reduced. A molded article of a styrenic polymer having a dyne / cm of 35 dyne / cm or more. 2. The styrene polymer molded article according to claim 1, wherein the molded article is a film, a sheet or a fibrous form. 3. The molded article of a styrene polymer according to claim 1, wherein the molded article is stretched in at least one direction. 4. A styrenic polymer having a syndiotactic structure or a composition of the polymer, wherein at least a part of the surface is subjected to a chemical treatment and / or a physical treatment, and the surface tension of the treated part is reduced. A molded article of a styrene-based polymer having improved printability, peel strength and adhesive application property, having a dyne / cm of 35 dyne / cm or more. 5. A styrenic polymer having a syndiotactic structure or a composition of the polymer, wherein at least a part of the surface is subjected to a chemical treatment and / or a physical treatment, and the surface tension of the treated part is reduced. A styrene polymer film or sheet for printing characterized by having a dyne / cm of at least 35 dyne / cm. 6. A styrenic polymer having a syndiotactic structure or a composition of the polymer, wherein at least a part of the surface is subjected to a chemical treatment and / or a physical treatment, and the surface tension of the treated part is reduced. A styrene-based polymer film or sheet for adhesive-coated laminations, having a dyne / cm of at least 35 dyne / cm.