JPH0637565B2 - Roughened film and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is excellent in the appearance of surface irregularities and mechanical properties and is useful as a matte film for drafting, a reader for magnetic tape, wallpaper, synthetic paper, etc. And a method for producing the same.

[Conventional technology]

To roughen the film surface, generally, a so-called sand blasting method in which the surface of the film is roughened by blowing hard granular sand or the like, a method of coating a resin containing inorganic particles or the like on the film surface, a film resin Method in which inorganic particles such as silica and titanium oxide are kneaded in advance,
Alternatively, there is a chemical etching method in which the film surface is corroded with an acid, an alkali, a solvent or the like, and in the case of roughening a polyester film, it is mainly carried out by a sandblast method or a coating method.

On the other hand, a method for roughening the surface by adding an organic synthetic resin has been proposed. For example, Japanese Patent Publication No. Sho 55-12368 discloses a linear polyester resin, a polycarbonate, and two or more high molecular weight polymers other than those. Japanese Patent Publication No. 58-28096 discloses a combination of a linear polyester resin and a phenoxy resin, and Japanese Patent Publication No. 58-28097 discloses a combination of a linear polyester resin.

[Problems to be Solved by the Invention]

However, in these methods, since the roughening is not sufficiently expressed unless a large amount of the resin to be added is introduced, the cost is high, the surface irregularities are too rough, and the commercial value is difficult to obtain. It has been pointed out that the mechanical performance of is likely to deteriorate, and other drawbacks.

The present invention has been made to solve the above-mentioned problems in production and performance of a polyester-based surface-roughened film by an organic synthetic resin addition method.

[Means for Solving the Problems]

As a result of repeated studies on the polyester-based surface-roughened film by the method of adding an organic synthetic resin, the present inventors found that blending a thermoplastic polyamide having a high glass transition temperature with the polyester forming the film is suitable for solving the above problems. And arrived at the present invention.

That is, the present invention is a film comprising a mixture of a thermoplastic polyester (A) as a sea component, a thermoplastic polyamide (B) having a higher glass transition temperature than the thermoplastic polyester (A) as an island component, or a mixture thereof. A film laminated so as to form a surface layer, the gist is a roughened film characterized in that the film surface has fine protrusions having a thermoplastic polyamide (B) as a core, and further a thermoplastic polyester ( An unstretched film composed of a mixture containing (A) a sea component and a thermoplastic polyamide (B) having a higher glass transition temperature than the thermoplastic polyester (A) as an island component, or laminated so that the mixture forms a surface layer. The unstretched film thus obtained is stretched at a temperature intermediate between the glass transition temperatures of the thermoplastic polyester (A) and the thermoplastic polyamide (B). A method of manufacturing a beam.

Representative examples of the thermoplastic polyester (A) in the present invention include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene-2,6-naphthalate (PEN), poly-1,4-cyclohexylene dimethylene terephthalate (PCT). ) Or poly-p-ethyleneoxybenzoate (PEOB), which sufficiently satisfies the requirements such as performance and price as a polyester for films. Here, the glass transition temperature (hereinafter, referred to as Tg) of the thermoplastic polyester (A) plays an important role in the relationship with the Tg of the thermoplastic polyamide (B).
It can be measured by the C method. Tg of PET is 70 ° C., Tg of PBT is 50 ° C., Tg of PEN is 120 ° C.
℃, PCT Tg is 95 ℃, PEOB Tg is 60 ℃,
Is a general value. Further, other components may be introduced as a copolymerization component into these thermoplastic polyesters to the extent that the film-forming ability is not impaired, and the polyester may be formed of a mixed polyester of PET and PBT, for example. Needless to say.

Next, the thermoplastic polyamide (B) used in the present invention
Is a thermoplastic polyamide having a Tg higher than that of the thermoplastic polyester (A), and the requirement for the Tg value is as follows.

That is, the thermoplastic polyester (A) and the thermoplastic polyamide (B), the thermoplastic polyester (A) is a sea component, the thermoplastic polyamide (B) is melt-mixed to form an island component, extruded into a film shape. , Which is further stretched into a roughened film, and when the Tg of the thermoplastic polyamide (B) is low, the thermoplastic polyester (A) is stretched.
This is because the thermoplastic polyamide (B) cannot grow as a core and the protrusions on the film surface that are essential are not developed. The difference in Tg between the thermoplastic polyester (A) and the thermoplastic polyamide (B) is preferably 20 ° C. or higher, more preferably 30 ° C. or higher.

Examples of such a high Tg polyamide include 5-tert. Butylisophthalic acid, 1,1,3-trimethyl-3-phenylindane-3 ', 5-dicarboxylic acid, 3-aminomethyl-3,
5,5-Trimethyl-cyclohexylamine, 1,3-diaminocyclohexane, metaxylenediamine, 1,3-bis (aminomethyl) cyclohexane, 2,4,4-trimethylhexamethylenediamine, bis (4-aminocyclohexyl) methane Polyamide containing a component such as bis (3-methyl-4-aminocyclohexyl) methane as a copolymerization component is suitable, and ethylenediamine, tetramethylenediamine, hexamethylenediamine, phenylenediamine, adipic acid, sebacic acid, cyclohexanedicarboxylic acid. Acid, isophthalic acid, terephthalic acid, naphthalene dicarboxylic acid, ε-aminocaproic acid, ω-aminododecanoic acid, aminobenzoic acid, ε-caprolactam and the like and appropriately combined with a polyamide-forming component polycondensation by a commonly known method can get. In addition, thermoplastic polyamide
The higher the Tg of (B), the easier the roughening effect is, but
200 ° C considering the processability during polycondensation or melt molding
The following is preferable.

In the roughened film of the present invention, the thermoplastic polyamide (B) serves as an island component and is a thermoplastic polyester of the sea component.
Although it is dispersed in (A), the thermoplastic polyamide (B) is preferably as spherical as possible, and it is preferable that the thermoplastic polyamide (B) exists with a particle size of submicron to micron order. The amount of the thermoplastic polyamide (B) in is preferably 3 to 30% by weight, more preferably 5 to 20% by weight.

In the roughened film of the present invention, the thermoplastic polyamide (B) is used as a core to form fine protrusions on the film surface, and the surface roughness of the film varies depending on the use and purpose, but generally the center plane 0.1 in average roughness (SRa)
μm or more, preferably 0.2 μm or more,
If it is too coarse, it will be difficult to write clearly.
μm or less is preferable. SRa represents the average distance of the peaks and troughs from the center plane, with the plane where the sum of the peak areas and the sum of the valley areas on the film surface is the same. Specifically, for example, a method of measuring with a three-dimensional surface roughness meter manufactured by Kosaka Laboratory is suitable.

The roughened film of the present invention is a thermoplastic polyester (A)
The mixture may be composed of a mixture of the thermoplastic polyamide (B) and the thermoplastic polyamide (B) alone, or may be in the form of multiple layers. The latter is a film in which a layer composed of the mixture is laminated with another polymer layer so as to form a surface layer on one side or both sides of the film, which leads to improvement in mechanical properties, cost reduction and the like. As the "other polymer", polyesters such as PET, PBT, PEN, PCT and PEOB are preferably used because of their mechanical properties and ease of production.

The surface-roughened film of the present invention, as described at the beginning, an unstretched film composed of a mixture of a thermoplastic polyester (A) and a thermoplastic polyamide (B), or a thermoplastic polyester (A) and a thermoplastic polyamide (B). And a thermoplastic polyester (A) and a thermoplastic polyamide (B) are stretched at a temperature intermediate between the Tg of the thermoplastic polyester (A) and the thermoplastic polyamide (B). The film can be produced by a generally known method. That is, the thermoplastic polyester (A) and the thermoplastic polyamide (B) are melt-mixed with a uniaxial or biaxial extruder to finely disperse the thermoplastic polyamide (B) in the thermoplastic polyester (A), A method in which the obtained mixture is melt-extruded in a film form from a T die or a circular die alone or together with other polymers and then cooled with a casting roller or a gas or a liquid is a method. The unstretched film thus obtained has relatively smooth surface irregularities, but the stretched surface exhibits irregularities. At this time, the stretching temperature is thermoplastic polyester.
It is necessary that the temperature is intermediate between the Tg's of (A) and the thermoplastic polyamide (B). T of thermoplastic polyester (A)
At temperatures lower than g, stretchability is poor and thermoplastic polyamide
At temperatures higher than the Tg of (B), good surface irregularities are difficult to develop. In the case of uniaxial stretching, the stretching ratio is preferably 1.5 times or more. Further, a more favorable film can be obtained by biaxially stretching in the longitudinal and lateral directions. Also in this case, it is preferable to stretch the film in the length and width by 1.5 times or more.

The stretching method of the film is not particularly limited, but uniaxial stretching,
Sequential biaxial stretching, simultaneous biaxial stretching and the like can be applied. Further, as a stretching device used therefor, a two-roll type uniaxial stretching machine, a tenter type transverse stretching machine, a tenter type or tubular type simultaneous biaxial stretching machine and the like can be applied.

It is also possible to add an inorganic additive such as silica, titanium oxide, calcium carbonate, alumina, kaolin, mica or talc to the film of the present invention. These inorganic additives are thermoplastic polyester (A) and thermoplastic polyamide (B)
0.3 to 10% by weight, preferably 0.5 to
7% by weight is suitable and the average particle size is 0.01
˜5 μm is preferred. Since these inorganic particles are harder than the organic resin, the writing characteristics of the film, especially the pencil writing characteristics, can be improved.

〔Example〕

 Hereinafter, the present invention will be described in more detail with reference to Examples.

Reference Example Synthesis of High Tg Polyamide 45 mol% isophthalic acid, 5 mol% terephthalic acid, 35 mol% hexamethylenediamine, bis- (4-amino-)
3-Methylcyclohexyl) methane 15 mol%, acetic acid 0.
10 kg of the raw material in the proportion of 015 mol% was charged into the reaction vessel together with 8 kg of pure water, and the air in the reaction vessel was purged with nitrogen several times.
After raising the temperature to 90 ° C and reacting for about 5 hours,
The reaction temperature was gradually raised to 280 ° C. over 10 hours under pressure (18 bar) with stirring in the vessel.

Then, the pressure was released and the pressure was reduced to atmospheric pressure, and then polymerization was carried out at the same temperature for 6 hours. After the completion of the reaction, the product was discharged from the reaction tank and cut to obtain pellets. M of this polyamide
The relative viscosity measured at 20 ° C. at a concentration of 1 g / d in cresol was 1.50 and the Tg was 150 ° C.

(Examples 1 to 3) PET (A-1) and the polyamides obtained in Reference Example (B-
As shown in Table 1, 1) and 1) were melt-mixed at 280 ° C. using a twin-screw kneading extruder to form chips.

Next, these chips were melted at 280 ° C. with a 50 mmφ extruder and extruded from a T die to form a film having a thickness of about 500 μ. The obtained unstretched film was uniaxially stretched 3 times at 90 ° C. by a two-roll type uniaxial stretching machine. The composition conditions are shown in Table 1. All the stretched films had excellent mechanical properties and writing characteristics.

(Example 4) The unstretched film in Example 2 was simultaneously biaxially stretched at 100 ° C in a lengthwise and transverse direction of 3.3 times and heat set at 230 ° C. As for the properties of the obtained stretched film, good results were obtained as shown in Table 2.

(Example 5) Using a coextrusion film forming apparatus equipped with three 40 mm extruders, a 300μ polyethylene terephthalate layer was laminated in the center and 100μ each on both ends, a mixed resin layer having the same composition as in Example 2 was laminated. Made an unstretched film. This unstretched film was rolled at 90 ° C in a longitudinal direction by a roll-type longitudinal stretching machine to obtain 3.3
The film was double-stretched, then 3.4-fold stretched in the transverse direction by a tenter type stretching machine at 100 ° C., and immediately heat-set at 230 ° C.

The surface roughness of the stretched film is as shown in Table 3,
The writing characteristics were also good. The mechanical properties were also good as shown in Table 3.

(Example 6, Comparative Examples 1-2) In the reference example, polycondensation was performed using sebacic acid instead of terephthalic acid, and polyamide (B-
2) was obtained. Using this polyamide (B-2) and the above-mentioned polyamide (B-1) and PEN (A-2), a fourth
A uniaxial stretching test was conducted in the same manner as in Examples 1 to 3 with the composition and stretching temperature shown in the table. As is clear from this table, the Tg of polyamide and the stretching temperature play a very important role in roughening the film.

[Effects of the Invention] The surface-roughened film and the method for producing the same according to the present invention make it possible to realize a surface-roughened film using an organic synthetic resin blend, which has been considered difficult in the past. It has extremely high industrial value in terms of productivity, mechanical properties, and unevenness performance.

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Claims (2)

[Claims] 1. A thermoplastic polyester (A) as a sea component,
A film comprising a mixture containing a thermoplastic polyamide (B) having a glass transition temperature higher than that of the thermoplastic polyester (A) as an island component, or a film in which the mixture is laminated so as to form a surface layer, the film comprising: A roughened film having a surface having fine projections having the thermoplastic polyamide (B) as a core. 2. A thermoplastic polyester (A) as a sea component,
An unstretched film composed of a mixture containing a thermoplastic polyamide (B) having a glass transition temperature higher than that of the thermoplastic polyester (A) as an island component, or an unstretched film laminated such that the mixture forms a surface layer. A method for producing a surface-roughened film, which comprises stretching at a temperature intermediate between the glass transition temperatures of the thermoplastic polyester (A) and the thermoplastic polyamide (B).