JPH04152136A - Laminated polyester film - Google Patents

Abstract

PURPOSE:To provide the title film having good releasability with respect to a self-adhesive or the mutual adhesion of films and usable even under a high temp. and high humidity condition by using polyester containing a specific amount of a polysiloxane/polyester block copolymer having a specific MW at least on a single surface. CONSTITUTION:A laminated polyester film is constituted so that at least the single surface thereof is composed of polyester containing 1-40wt.% of a polyorganosiloxane/polyester block copolymer consisting of polymers represented by formulae I, II. The wt. ratio of the polymers represented by the formulae I, II of the polyorganosiloxane/polyester block copolymer is 90/10-30/70 and the MW thereof is 600-40000. By this constitution, the laminated polyester film arbitrarily controlled in two characteristics of the adhesiveness and relaseability with a self-adhesive with respect to both surfaces of the film can be obtained. Since the polysiloxane/polyester block copolymer is well polymerized with polyester, said copolymer can be prepared with good operability without requiring a special treatment process such as a surface treatment method and has excellent durability.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention provides a polyester with excellent releasability, in which at least one surface is made of polyester copolymerized with 1 to 40 percent polyorganosiloxane/polyester block copolymer. The present invention relates to a laminated polyester film having a surface that is

(Prior Art) As is well known, polyester films are used for various purposes due to their excellent mechanical properties, electrical insulation properties, thermal properties, etc., and are used in magnetic tapes, capacitor films, adhesive tapes, and release It is widely used in shape films and packaging films.

In such applications, for example, when used as a release film for adhesive tapes, labels, patches, etc., one surface must firmly adhere to the adhesive, but the other surface must adhere firmly to the adhesive. It is necessary for the film to be easily peeled off, and until now one side of the film has been coated with silicone or the like to make it non-adhesive.

Additionally, surface coating films (processing paper) for glass fiber-reinforced epoxy resin substrates are also treated with silicone on both sides of the film.

(Problem to be solved by the invention) However, such conventional techniques have complicated processes,
Silicone may not be applied evenly, causing problems in controlling and managing peelability, silicone may migrate to the adhesive, resulting in poor adhesion and no adhesion, or it may be difficult to use in hot and humid environments. There were drawbacks such as:

There is also a method of simply blending silicone with polyester, but polyester and silicone have poor affinity.
In addition, the reactivity is poor, probably because there are few reactive groups at the ends that react with polyester, and as a result, silicone stains appear on the rolls of the film forming equipment! There were also drawbacks such as silicone bleeding out on the film surface.

(Means for Solving the Problems) As a result of intensive research to solve the above problems, the present inventors have discovered that at least a polyester containing a specific amount of a polysiloxane/polyester block copolymer having a specific molecular weight has If you use laminated polyester on one side,
The present invention was achieved based on the discovery that it has good releasability from adhesives and films, has no roll stains or bleed-outs, and can be used without problems even under high temperature and high humidity conditions.

That is, the present invention relates to a laminated polyester film in which at least one surface is composed of a polyester obtained by copolymerizing 1 to 40% by weight of a polyorganosiloxane/polyester block copolymer represented by the following formula.

The weight ratio of (I) and (II) in the polyorganosiloxane/polyester copolymer is 90/1o to 3°/7.
0, and the molecular weight is 600 to 40,000.

CH.

(-Si-0-)m (I)CH3 (In the formula, m represents a number from 100 to 30,000.)OR
.

(-C-(CHz)p-C)l-0-)n (
II) (where p is an integer from 1 to 6; n is 1 to 400
an integer of R1 is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aralkyl group, an alkenyl group having 1 to 18 carbon atoms, and an acyl group. ) In the present invention, the film constituting at least one surface is made of polyester copolymerized with a polyorganosiloxane/polyester block copolymer (polyester A
), and the polyorganosiloxane/polyester block copolymer in the present invention is a block copolymer consisting of a polyorganosiloxane block and a polyester block obtained by ring-opening polymerization of a cyclic lactone in the molecule. The block copolymers can be roughly classified as follows.

■ Direct ring-opening polymerization of a cyclic lactone to a modified polyorganosiloxane having an alcoholic hydroxyl group, and if necessary, etherification of the terminal hydroxyl group with an alkyl halide, etc., or organic carboxylic acids or their ester-forming derivatives, etc. acylate with

■ A ring-opening polymer mainly composed of cyclic lactones, which has a reactive group such as a carboxyl group, a hydroxyl group, or an ethylenically unsaturated double bond at the end, is modified to have a functional group that reacts with the reactive group. React with polyorganosiloxane.

The modified polyorganosiloxane used to produce the block copolymer of the present invention includes a modified polyorganosiloxane having a 5i-H bond, and a functional group bonded to the silicon atom of the polyorganosiloxane via an alkylene group. There are various modified polyorganosiloxanes, and more specifically, alcohol-modified polyorganosiloxanes having hydroxymethyl groups, hydroxyethyl groups, hydroxypropyl groups, etc., and amino-modified polyorganosiloxanes having aminoethyl groups, aminopropyl groups, etc. , carboxylic acid-modified polyorganosiloxanes having carboxyethyl, etc., mercapto-modified polyorganosiloxanes having mercaptopropyl, etc., and polyethers in the form of addition polymerization of alkylene oxides such as ethylene oxide and propion oxide to these functional groups. Examples include polyether-modified polyorganosiloxanes having the following properties. Among these, alcohol-modified polyorganosiloxane and carboxylic acid-modified polyorganosiloxane are preferred because they are easy to manufacture and have excellent heat resistance themselves.

On the other hand, examples of the lactone used to produce the copolymer of the present invention include β-propiolactone, δ-valerolactone, and ε-caprolactone, with ε-caprolactone being preferred.

The block copolymer of the present invention is polyorganosiloxane block/polyester block 90/10
~30/70 (each % by weight), preferably 70/30~
It consists of 40/60 (each % by weight). If it is out of this range, the resulting copolymer may have poor reactivity with polyester or silicone may bleed out onto the film surface, which is not preferable. In addition, the polyorganosiloxane block has a molecular weight of 100 to 3.
A value in the range of 0,000 is preferable, and 4000 to 20.
A range of 000 is more preferred.

In the present invention, polyorganosiloxane/polyester block copolymer is copolymerized with polyester, and the copolymerization amount needs to be 1 to 40% by weight, preferably 10 to 30% by weight, more preferably 15 to 40% by weight. 25% by weight is good. If the copolymerization amount is less than 1% by weight, the effect of imparting release properties is insufficient, and if it exceeds 40% by weight, the effect not only becomes saturated, but also the melt viscosity becomes too high.
The melting point decreases, making it difficult to form a film, and the properties of the polyester film are impaired.

A specific method for producing the polyester obtained by copolymerizing the polyorganosiloxane/polyester block copolymer according to the present invention will be described below.

First, terephthalic acid (TPA) and ethylene glycol (EG) are added to the esterification reactor where the esterification reaction products are present.
slurry (TPA/EG molar ratio 1/1.2 to 1/1
.

8) is continuously supplied, 0.5Kg/c+m'' to 1.
The esterification reaction is carried out at a temperature of 240°C to 270°C under pressure of 5 kg of nitrogen to continuously obtain an esterified reaction product.

The obtained esterified product was transferred to a polymerization reactor, the required amount of polyorganosiloxane/polyester block copolymer was added thereto, and then the mixture was heated at a temperature of 270°C to 290°C for 0.
A polycondensation reaction is carried out under reduced pressure of 1 Torr or less for 5 to 5 hours to obtain a predetermined intrinsic viscosity, thereby obtaining a polyester copolymerized with the polyorganosiloxane/polyester block copolymer of the present invention.

The polycondensation reaction is usually carried out in the presence of a polycondensation catalyst, using commonly used metal compounds such as antimony, germanium, tin, titanium, and cobalt, and sulfosalicylic acid and 0-sulfobenzoic anhydride. Organic sulfonic acid compounds are used.

In addition, the said catalyst can also be added beforehand in an esterification process.

In addition, in the present invention, the polyester (polyester B) constituting the other side of the film is mainly composed of polyethylene terephthalate having ethylene terephthalate as a repeating unit, but includes isophthalic acid, p-oxybenzoic acid, 5=sodium Sulfoisophthalic acid, adipic acid, trimellitic acid, propylene glycol, 1.4
- Polyester containing cyclohexane dimetatool, pentaerythritol, etc. as a copolymer component can also be applied as long as it can be formed into a film and stretched.

When the laminated polyester film of the present invention is used for an adhesive tape, for example, polyester A copolymerized with a polyorganosiloxane/polyester block copolymer is used.
After forming an unoriented film with a two-layer laminate structure consisting of a layer composed of B and another layer composed of polyester B which is not copolymerized with polyorganosiloxane/polyester block copolymer, this is stretched. Manufactured by

When used as a surface coating film for glass fiber reinforced epoxy resin substrates, an unoriented film with a laminate structure of at least three layers, an outer layer made of polyester A and an inner layer made of polyester B, is used. After forming, it is manufactured by stretching it.

In the manufacturing process of the non-oriented film, polyester A constituting one surface layer and polyester B constituting the other side may be laminated and extruded by a coextrusion method, and
After being extruded separately from a separate die, the laminated unoriented film can be subjected to stretching.

The stretching process that follows the forming process of the laminated non-oriented film can be freely selected from conventionally known film stretching methods, such as simultaneous biaxial stretching, two-stage two-wheel stretching, -axial stretching, etc., depending on the purpose. be able to.

(Function) Since the laminated polyester film of the present invention uses polyester copolymerized with polyorganosiloxane/polyester block copolymer for at least one surface layer, it has good releasability from the adhesive and The surface layer made of polyester that is not copolymerized with the polyorganosiloxane/polyester block copolymer firmly adheres to the adhesive.

Furthermore, since the polyorganosiloxane/polyester block copolymer and polyester are copolymerized, there are no problems such as roll staining of the film forming apparatus or bleed-out of the film surface.

(Example) Hereinafter, the present invention will be specifically explained with reference to Examples.

In addition, in the examples, the intrinsic viscosity [η] of the polymer is 2
It is calculated from the value measured at 0°C, and the peeling force of the polyester film was determined by conducting the following test.

(1) Peeling force A laminated polyester film was applied to an acrylic adhesive tape (Nitto Tape N31B), and the 180° peeling force was measured.

Reference Example 1 An example of producing a polyorganosiloxane/polyester block copolymer in the present invention is listed below.

A modified polydimethylsiloxane having hydroxypropyl groups at both ends (molecular weight 8.500
, hereinafter referred to as terminal bishydroxypropyl-modified polydimethylsiloxane), the contents were heated to 150°C, and 15 kg of ε-caprolactone was gradually added dropwise with stirring. After dropping, heat the mixture at 160°C for 5 hours.
After cooling to 70°C, 364g of acetic anhydride was added and the contents were heated to 140°C. The produced acetic acid was removed under reduced pressure to obtain a polyorganosiloxane/polyester block copolymer having a molecular weight of 15,000.

Reference Examples 2 to 4 Molecular weight is 2,000.4,500.15,000.35
,000 terminal bishydroxypropyl-modified polydimethylsiloxane was carried out in the same manner as in Reference Example 1, and the molecular weight was 4.500, 10,000.30.000.60.0.
Example 1 in which a polyorganosiloxane/polyester block copolymer of No. 00 was obtained. A slurry of TPA and EG was placed in an esterification reactor containing bis(β-hydroxyethyl) terephthalate and its low polymer (hereinafter referred to as 81 (hereinafter referred to as ET)). (TPA/EG molar ratio 1/1.6) was continuously supplied at a temperature of 250
B) with an esterification reaction rate of 95% by reacting at a pressure of 0.05 Kg/cm"G and a residence time of 8 hours.
IET was obtained continuously.

50 kg of this BHET was transferred to a polymerization tank and heated to 280°C, and antimony trioxide was added as a catalyst in an amount of 2 Xl0-4 mol per 1 mol of the acid component constituting the polyester, and the polymer with a molecular weight of 15,000 obtained in Reference Example 1 was A polyorganosiloxane/polyester block copolymer was added in an amount of 20% by weight based on the polyester produced. After that, 280
Polycondensation was finally carried out at 0.1°C for 2.5 hours under reduced pressure of 0.1 Torr to obtain a polyester with [η) = 0.63.

Polyethylene terephthalate copolymerized with the obtained polyorganosiloxane/polyester block copolymer was prepared as a resin for one surface layer, and polyethylene terephthalate with [η) = 0.71 was prepared as a resin for the other surface layer. Polyethylene terephthalate copolymerized with a 60 μm polysiloxane/polyester copolymer was produced using a T-die extrusion device consisting of a 905 m diameter extruder for one surface layer and a 65 wm diameter extruder for the other surface layer. An unstretched film having a two-layer structure consisting of a surface layer and another surface layer of polyethylene terephthalate having a thickness of 60 μm was molded.

The unstretched film was stretched at a stretching temperature of 95° C. using a tenter-type simultaneous two-wheel stretching machine set at a magnification of 3.0 times in the vertical direction and 3.5 times in the horizontal direction.
A laminated polyester film having a thickness of 12 μm was obtained by simultaneous two-wheel stretching under the following conditions.

The peel force of the obtained laminated polyester film was measured. The results are listed in Table 1.

Examples 2 to 5 and Comparative Examples 1 to 4 The polyorganosiloxane/polyester block copolymers of various molecular weights obtained in Reference Examples 2 to 4 were added in the amounts shown in Table 1, and the A laminated polyester film was obtained by carrying out the same procedure.

However, in Comparative Example 2, the produced polyester could not be discharged as a uniform strand, and in Comparative Example 4, it became lumpy during polycondensation and could not be discharged.
It was not possible to obtain a film for film formation.

The peel force of the obtained laminated polyester film was measured. The results are listed in Table 1.

Comparative Example 5 Polyethylene terephthalate having [η] = 0.71 was formed into a film by a conventional method and stretched to obtain a polyethylene terephthalate single layer film, and the peel force was measured in the same manner as above. The results are shown in Table 1.

Comparative Example 6 In Example 1, polyester was produced using polydimethylsiloxane with a molecular weight of 50,000 instead of the polysiloxane/polyester copolymer, and an attempt was made to form a film, but the dispersion of polydimethylsiloxane was poor. Film breakage occurred frequently and film formation could not be performed.

Table 1 (Effects of the Invention) As described above, the present invention provides a laminated polyester film in which the two properties of adhesiveness and releasability to adhesives are arbitrarily controlled on both sides of the film. be done.

Furthermore, since the polysiloxane/polyester block copolymer copolymerizes well with polyester, the film of the present invention can be manufactured with good operability, and does not require special treatment steps such as surface treatment. It can be manufactured easily and has excellent durability.

Patent applicant: Nihon Ester Co., Ltd.

Claims (1)

[Claims] (1) A laminated polyester film in which at least one surface is composed of a polyester obtained by copolymerizing 1 to 40% by weight of a polyorganosiloxane/polyester block copolymer represented by the following formula. The weight ratio of (I) and (II) in the polyorganosiloxane/polyester block copolymer is 90/10 to 3.
0/70, and the molecular weight is 600 to 40,000. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, m indicates a number from 100 to 30,000.)▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) (Here, p is 1 An integer of ~6. n is an integer of 1 to 400. R_1 is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aralkyl group, an alkenyl group having 1 to 18 carbon atoms, It is a group selected from acyl groups.)