JPH03124736A - Molded article of styrenic polymer - Google Patents

Abstract

PURPOSE:To prepare the title molded article excellent in the printing properties, resistance to boiling, and adhesive properties by molding a styrenic polymer (compsn.) with a syndiotactic structure and specifically treating at least a part of the surface of the product to bring the surface tension of the treated part above a specified value. CONSTITUTION:A styrenic polymer (compsn.) (e.g. polystyrene) with a syndiotactic structure is molded, and at least a part of the surface of the product is subjected to a chemical treatment (e.g. a treatment with a chemical) and/or a physical treatment (e.g. corona discharge) to bring the surface tension of the treated part to 35dyne/cm or higher.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a molded article of a styrenic polymer, and more specifically to a molded article made of a specific material, which is obtained by subjecting the surface of the molded article to a certain treatment. This invention relates to a molded article with improved surface tension.

[Problems to be solved by conventional techniques and inventions] Conventionally,
For molded products made of polyolefins such as polyethylene and polypropylene, atactic polystyrene, polyethylene terephthalate, etc., printing on the surface and lamination that is normally performed are aimed at improving printability and adhesive strength of lamination, and reducing surface tension. Improvements are known.

However, although the surface tension of these resins has been improved, the physical properties of the resins themselves are insufficient, so that their uses have been limited. For example, polyolefin and atactic polystyrene lack heat resistance, and polyethylene terephthalate has problems with water resistance and moisture resistance. Therefore, these cannot withstand use under harsh environments.

The styrenic polymer with a syndiotactic structure proposed by the present inventors has properties such as heat resistance, chemical resistance, water resistance,
It has excellent electrical insulation properties, and especially its stretched products (films, sheet fibers) have excellent two-dimensional stability in mechanical properties, 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 has excellent heat resistance 5 water resistance, moisture resistance, etc. compared to the above conventional resins, but it can be melt-molded or Molded objects such as films and sheets obtained by stretch molding etc. are 1. Its surface tension is low, and its suitability for printing, lamination, etc. has not always been satisfactory.

Therefore, the present inventors have conducted intensive research to develop a molded article having surface properties suitable for printing, lamination, etc. using this styrene polymer having excellent physical properties.

As a result, the surface of the molded body made of a styrenic polymer with a syndiotactic structure is chemically coated.

It has been discovered that the desired molded article can be obtained by subjecting it to physical treatment. The present invention was completed based on this knowledge.

(Means for Solving the Problems) That is, the present invention consists of a styrenic polymer having a syndiotactic structure or a composition of the polymer, and at least a portion of the surface thereof is chemically and/or physically treated. The surface tension of the treated area is 35 dyne/c.
The object of the present invention is to provide a molded article of a styrenic polymer, characterized in that the styrenic polymer has a particle diameter of m or more.

The styrenic polymer having a syndiotactic structure used in the present invention refers to a phenyl group or substituted phenyl group whose stereochemical structure is a syndiotactic structure, that is, a phenyl group or substituted phenyl group that is a side chain with respect to the main chain formed from carbon-carbon bonds. It has a three-dimensional structure in which the carbon atoms are alternately located in opposite directions, and its cuticity is determined by nuclear magnetic resonance method (13) using carbon isotopes.
quantified by C-NMR method). ``Toughness measured by the C-NMR method is determined by the proportion of consecutive constituent units, e.g.
The styrenic polymer having a syndiotactic structure referred to in the present invention is usually 75% or more, preferably 85% or more, Or polystyrene having syndiotacticity of 30% or more, preferably 50% or more in racemic pentads.

Refers to poly(alkyl styrene), poly(halogenated styrene), poly(alkoxystyrene), poly(vinyl benzoate), hydrogenated polymers thereof, mixtures thereof, or copolymers containing these structural units. do. In addition, examples of poly(alkylstyrene) include poly(methylstyrene), poly(ethylstyrene), and poly(propylstyrene).

Poly(butylstyrene), poly(phenylstyrene).

Poly(vinylnaphthalene), poly(vinylstyrene).

Poly(acenaphthylene), etc. Poly(halogenated styrene) includes poly(chlorostyrene).

Examples include poly(bromostyrene) and poly(fluorostyrene). Furthermore, examples of poly(alkoxystyrene) include poly(methoxystyrene) and poly(ethoxystyrene). Among these, a particularly preferred styrenic polymer is polystyrene.

Poly(p-methylstyrene), poly(m-methylstyrene), poly(p-tert-butylstyrene).

Examples include poly(p-chlorostyrene), poly(m-chlorostyrene), poly(ρ-fluorostyrene), and a copolymer of matastyrene and p-methylstyrene (Japanese Unexamined Patent Publication No. 187708/1982). .

Furthermore, as comonomers in the styrenic copolymer, in addition to the above-mentioned styrene polymer heptamers, olefin monomers such as ethylene, propylene, butene, hexene, and octene, diene monomers such as butadiene and isoprene, and cyclic dienes are used. monomer and methyl methacrylate,
Examples include polar vinyl monomers such as maleic anhydride and acrylonitrile.

In addition, this styrene polymer has a weight average molecular weight of 10,000 or more and 3,000 or more, although there is no particular restriction on the molecular weight.
0,000 or less is preferred, especially 50.00
The optimum value is 0 or more and 1,500,000 or less.

If the weight average molecular weight is less than 10,000, sufficient stretching cannot be achieved. Furthermore, there are no restrictions on the width or narrowness of the molecular weight distribution, and various values can be used, but the weight average molecular weight (Mw)/number average molecule l (M
n) is preferably 1.5 or more and 8 or less.

Note that this styrenic polymer having a syndiotactic structure has much better heat resistance than conventional styrenic polymers having an active structure.

Styrenic resins having such a syndiotactic structure can be produced using styrenic monomers, for example, in an inert hydrocarbon solvent or in the absence of a solvent, using a titanium compound and a condensation product of water and trialkylaluminum as a catalyst. (a monomer corresponding to the above-mentioned styrenic polymer)
Publication No.).

Further, poly(halogenated alkyl styrene) can be obtained by the method described in JP-A-1-46912, and hydrogenated polymers thereof can be obtained by the method described in JP-A-1-178,505.

The material used in the present invention basically consists of the above-mentioned styrene polymer, but this styrenic polymer is combined with other commonly used resins, rubber, inorganic fine particles, antioxidants, nucleating agents, and plasticizers. , a compatibilizer, a coloring agent, an antistatic agent, and the like may be added.

Inorganic fine particles that can be suitably used here include group IA,
Group IIA, Group IVA, Group VIA, Group ■A, Group ■.

Oxides of Group IB, Group IIB, Group IIIB, Group IVB elements.

hydroxides, sulfides, nitrides, halides, carbonates,
Examples include acetates, phosphates, phosphites, organic carboxylates, silicates, titanates, borates and their hydrated compounds, complex compounds centered on these, and natural mineral particles. Specifically, lithium fluoride, Group IA element compounds such as borax (sodium borate hydrate), magnesium carbonate, magnesium phosphate, magnesium oxide (magnesia), magnesium chloride, magnesium acetate, magnesium fluoride, magnesium titanate, and magnesium silicate. , 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, barium phosphite HA group element compounds such as titanium dioxide (titania), -titanium oxide, titanium nitride, zirconium dioxide (zirconia), -IVA group element compounds such as -zirconium oxide, VIA group elements such as molybdenum dioxide, molybdenum trioxide, molybdenum sulfide, etc. Compounds of ■group A elements such as manganese chloride and manganese acetate; compounds of group ■ elements such as cobalt chloride and cobalt acetate; compounds of group IB elements such as cuprous iodide; compounds of group IIB elements such as zinc oxide and zinc acetate. , TIIB group element compounds such as aluminum oxide (alumina), aluminum hydroxide, aluminum fluoride, aluminosilicate (alumina silicate, kaolin, kaolinite), silicon oxide (silica, silica gel), graphite, carbon, graphite glass, etc. Group IVB element compounds, carnalite, kainite, mica (
Examples include particles of natural minerals such as mica, phlegm), villose ore, etc. The average particle size of the inorganic fine particles is not particularly limited, but is preferably 0.01 to 100 um, more preferably 0.01 to 3 um, and the content in the composition is 0.01 to 100 um, more preferably 0.01 to 3 um.
0.001 to 3% by weight, preferably 0.001 to 1% by weight.

In addition, although the above-mentioned inorganic fine particles are effective components for improving the slipperiness of the surface of the molded product, other types of fine particles or other particle sizes, or inorganic fillers may be used as long as they do not impede the purpose of the present invention. etc. may also be included.

The above-mentioned inorganic fine particles are used for the final molded product, that is, a film,
Although it is contained in sheets etc., there is no limitation on the method of containing it. Examples include a method of adding or precipitating the styrenic monomer at any step during polymerization, and a method of adding at any step of melt extrusion.

On the other hand, there are various other resins that can be used together with the above-mentioned styrenic polymer having a syndiotactic structure. Polymers, styrene-maleic anhydride copolymers, polyphenylene ethers, etc. are not compatible with the above-mentioned syndiotactic structure styrenic polymers (preformed objects for stretching (raw sheets, films, etc.) It is effective in controlling crystallization during the production of film, improves the subsequent stretchability, makes it easy to control stretching conditions, and makes it possible to obtain a film with excellent mechanical properties. / Or when containing a styrene polymer with an isotactic structure, it is preferable to use a styrene polymer similar to the styrene polymer with a syndiotactic structure.Also, the content ratio of these compatible resin components is 70 to 70%. It may be 1% by weight, particularly preferably 50 to 2% by weight.If the content of the compatible resin component exceeds 70% by weight, the heat resistance, which is an advantage of a styrene polymer with a syndiotactic structure, may be reduced. This is not preferable because it damages the following properties.

In addition, examples of the incompatible resin include polyethylene,
Polyolefins such as polypropylene, polybutene, and polybentene; polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyamides such as nylon-6 and nylon 6.6; polythioethers such as polyphenylene sulfide; polycarbonate; polyarylate; polysulfone; Ether ether ketone, polyether sulfone, polyimide, vinyl halide polymers such as Teflon, acrylic polymers such as polymethyl methacrylate, polyvinyl alcohol, etc., except for the compatible resins listed above, are equivalent.
Further examples include crosslinked resins containing the above-mentioned compatible resins. These resins are incompatible with the styrenic polymer having a syndiotactic structure of the present invention, so if they are contained in small amounts, they cannot be dispersed like islands in the styrenic polymer having a syndiotactic structure. It is effective in imparting a suitable gloss after stretching and improving surface slipperiness.

The content ratio of these incompatible resin components is preferably 50 to 5% when gloss is desired, and 0.001 to 5% when the purpose is to control surface properties. Furthermore, if 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 formed from the above-mentioned materials, and there are no particular limitations on its form. Specifically, it contains at least one layer composed of the above styrene polymer or the composition, and after heating and melting,
A sheet-like, film-like, or fibrous molded product that is extruded into a planar, linear, bicylindrical, etc. configuration with at least one layer, cooled and solidified, or a molded product obtained by stretching the molded product in at least one direction. , or a composite body (laminated film woven fabric, etc.) containing at least the above-mentioned molded body in its structure.

In the present invention, the surface (part or all) of such a molded body
is subjected to chemical surface treatment and/or physical surface treatment, and the surface tension of the surface-treated portion of the molded body is reduced to 35 dyn.
The characteristic is that it is equal to or more than e/cm. The chemical and physical surface treatment carried out here can be carried out by various methods without particular limitations, as long as the surface tension of the molded article can be set to 35 dyne/cm or more after the surface treatment. Specifically, the following can be mentioned.

First, chemical treatments mainly include wet treatments, such as (1) immersing the molded body in various chemicals to introduce the desired functional group, in the present invention, a carbonyl group, onto the surface. Chemical treatment to form a porous structure,■
Coupling agent treatment, in which the molded body is immersed in a silyl peroxide solution containing a silane-based, titanium-based, or chromium-based coupling agent to form a surface layer; ■ Monomer-polymer coating treatment, in which the surface of the molded body is coated with an arbitrary monomer or polymer. , (2) Steam treatment in which steam of various compounds is applied to the surface of the molded body, the surface is etched by the steam, and the components of the steam are introduced into the surface-treated portion through a reaction between the components of the steam and the surface of the molded body, (2) Molding. Examples include surface grafting treatment in which a compound having an oxygen-containing functional group is graft-polymerized onto the body, and (2) electrochemical treatment in which the molded body is immersed in an electrolytic solution and the surface of the molded body is subjected to reduction treatment.

When performing such chemical treatment, since the styrenic polymer used in the present invention has excellent solvent resistance, it is necessary to use atactic solvents such as organic solvents with a solubility parameter of 7 to 12 (cal/c%). Inorganic (aqueous) solutions that can be used with polystyrene, gases, etc. are preferably used.

In addition, physical processing is mainly dry processing, but for example: (1) ultraviolet irradiation treatment in which the surface of the molded body is irradiated with ultraviolet rays to form carbonyl groups, and (2) blow discharge or corona discharge is applied to the surface of the molded body. Plasma treatment to form carbonyl groups, ■Plasma polymerization treatment to form a polymer film on the surface of the compact in carrier gas in a plasma state, ■Ion beam that accelerates ions and applies them to the surface of the compact to roughen the surface. Treatment: ■ Mechanical treatment that activates and roughens the surface using mechanochemical effects; ■ Flame treatment that oxidizes the surface by applying an oxidizing flame; ■ Ozone treatment that sprays high-concentration ozone between the films just before lamination. Examples include.

In the case of physical treatment, since the styrenic polymer of the present invention has excellent heat resistance, it can be treated at relatively high temperatures. Effective treatment can also be performed at temperatures above.

Therefore, it is possible to carry out effective surface treatment 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 surface treatment is important for subsequent processing (printing.

lamination, etc.), this is an extremely important factor.

Among these above methods, especially ultraviolet irradiation treatment,
Methods such as plasma treatment, flame treatment, and ozone treatment are suitable.

In the present invention, the surface tension is lowered to 35 dyne/cm by subjecting the surface of the molded article to one or more of the above-mentioned treatments, or by other methods other than the above-mentioned treatment methods. As mentioned above, the molded product preferably has a density of 37 dyne/cm or more. Here, if the surface tension of the molded article is less than 35 dyne/cm, the wettability of the surface will be poor, printing ink will not stick well to it, or adhesive strength will decrease, which is not preferable.

Incidentally, the surface tension in the present invention was measured according to JIS K6810 using a surface wetting reagent at 23° C. and 150% RH (relative humidity).

The thus obtained molded article of the present invention can be used for various purposes either alone or by laminating it with other resins or the like.

〔Example〕

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

Production Example 1 (Production of styrenic polymer) (1) Preparation of contact product of trimethylaluminum and water Copper sulfate pentahydrate (Cu S 04 ・5 Hz O)1
Add 7.8 g (71 mmol), 200 g of toluene and 24 d (250 mmol) of trimethylaluminum,
The reaction was carried out at 40°C for 8 hours. After that 1. From the solution obtained by removing the solid portion, toluene was further distilled off under reduced pressure at room temperature to obtain 6.7 g of a contact product. The molecular weight of this contact purified product was determined to be 610 by the pseudo-solid point depression method.

(2) Production of styrenic polymer In a reaction vessel with an internal volume of 21, 1 part of purified styrene was added to the above (1)
) A polymerization reaction was carried out at 90°C for 5 hours using 5 mmol of the contact product obtained in (1) as aluminum atoms, 5 mmol of triisobutylaluminum, and 0.025 mmol of pentamethylcyclopentagenyl titanium trimethoxide. . After the reaction was completed, the catalyst component of the product was decomposed with a methanol solution of sodium hydroxide, washed repeatedly with methanol, and then dried to obtain 308 g of a polymer. 1. 2.
The weight average molecular weight of this polymer measured by gel permeation chromatography at 130°C using 4-triclobenzene as a solvent was 389.000, and the weight average molecular fit/number average molecular weight was 2.64. .

Furthermore, it was confirmed by melting point and C-NMR measurements that this polymer was polystyrene with a syndiotactic structure.

Example 1 The polystyrene produced in Production Example 1 was extrusion molded at 320°C to obtain a sheet-like molded product. The degree of crystallinity of this sheet-like molded body was determined to be 14% using a differential scanning calorimeter. The sheet was sequentially stretched vertically and horizontally at a stretching ratio of 3 times to obtain a biaxially stretched film with a thickness of 15 μm. Furthermore, heat treatment was performed at 250°C.

The obtained film was treated with a corona treatment device (H
FS-203), 28 W/rri min
Corona treatment was performed under treatment density conditions of .

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 ■) were bonded with a two-component adhesive (AD-30 manufactured by Toyo Morton).
8A, AD-308B) to create a laminate film.

When the peel strength of the produced laminate film was measured, a value of 900 g was obtained, indicating that the adhesive strength was strong.

The surface tension was measured according to JIS K6810 using a surface wetting reagent at 23° C. and 50% RH, and the adhesive peel strength was measured using the T-peel method under the following conditions.

Peel strength measurement conditions: sample width 15 mm tensile speed 3 mm/min Example 2 The biaxially stretched film in Example 1 was treated with oxygen gas in a vacuum of Q, 5 Torr using a plasma processing apparatus prototyped by the present inventors. Plasma treatment was performed in an atmosphere.

The surface tension of the obtained film was 52 dyne/cm, and the printing ink (Volime GT) manufactured by Toyo Ink Co., Ltd.
When applied, there was no bleeding and printability was excellent, and even after boiling at 95°C for 130 minutes, there was no peeling with cellophane tape. Furthermore, this film showed almost no thermal deformation even when heated at 200°C for 30 minutes.

Example 3 In Example 2, the processing density condition was set to 14W/nf・wi
The same procedure as in Example 2 was carried out except that a polystyrene film having a surface tension of 40 dyne/cm was used as n. Printability and peeling test after boiling were good.

Comparative Example 1 In Example 1, the film was not subjected to corona treatment. The surface tension of this film was 33 dyne/cm, and when the same adhesive evaluation as in Example 1 was carried out, the peel strength was 300 g, which was unacceptable for practical use.

Comparative Example 2 The polystyrene produced in Production Example 1 was molded into a 400 μm thick sheet using a T-die.

The surface tension of this sheet is 34 dyne/cm,
Printability was evaluated in the same manner as in Example 2. As a result, when cellophane tape was applied and removed from the printed surface after coating and drying, it was found that the printed surface was easily peeled off, indicating that the printability was insufficient.

Comparative Example 3 In place of the polystyrene stretched film in Example 2, a surface-modified biaxially stretched polypropylene film (
Except for using Torefane 5645, made by Toshi.
When the same procedure as in Example 2 was carried out, the printability and boilability were good. However, when heated to 200°C, the film melted.

Comparative Example 4 The same operation as in Example 2 was carried out, except that a surface-modified biaxially stretched polyester film (manufactured by Toyobo, Ester Film E5100) was used instead of the polystyrene stretched film in Example 2. . Printability, 20
Although the heat resistance at 0°C was good, the polyester film as the base material became brittle due to hydrolysis after the boiling treatment, making it unusable.

〔Effect of the invention〕

As described above, the molded article of the styrenic polymer of the present invention has not only the excellent physical properties inherent to the polymer such as heat resistance, chemical resistance, mechanical strength, etc., but also has improved surface tension through surface treatment. It is. Therefore, the molded product of the present invention has excellent printability, boil resistance, and adhesion to other molded products, and can easily produce molded products such as strongly bonded laminates and sheet laminates.

Therefore, the molded article of the present invention can be used for various industrial purposes.

It is widely and effectively used as a material for packaging films, sheets, etc.

Claims (3)

[Claims] (1) Consisting of a styrenic polymer having a syndiotactic structure or a composition of the polymer, at least a portion of the surface is chemically and/or physically treated, and the surface tension of the treated portion is 35 dyne/ A molded article of a styrenic polymer, characterized in that it has a size of cm or more. (2) The molded article of the styrenic polymer according to claim 1, wherein the molded article is in the form of a film, sheet, or fiber. (3) The molded body of a styrenic polymer according to claim 1, wherein the molded body is stretched in at least one direction.