JPS62232476A - Adhesive tape - Google Patents

Abstract

PURPOSE:To provide an adhesive tape which has a low coefficient of friction and excellent resistance to lamellar breakage and is hardly broken even when drawn out abruptly at a high speed and at a large angle of drawing-out, by providing an adhesive layer on at least one side of a biaxially oriented polyester film contg. fine particles of a specified silicone resin. CONSTITUTION:In an early stage of a polycondensation reaction for the production of a polyester (a) having an intrinsic viscosity of 0.4-0.9 (in o-chlorophenol at 35 deg.C) such as a copolymer in which at least 80mol% of the entire dicarboxylic acid component is terephthalic acid and/or 2,6-naphthalenedicarboxylic acid and at least 80mol% of the entire glycol component is ethylene glycol, 0.03-1.0wt% fine silicone resin particle (b) having an average particle size of 0.1-4mu and a volume shape factor of 0.20-0.52, wherein at least 80wt% of a structured unit of formula I is composed of a trifunctional organosiloxane of formula II, is added to the reaction mixture and the polycondensation reaction is carried out. The resulting polyester (A) is molded into a film and the film is biaxially oriented. An adhesive layer (B) is provided on at least one side of the film.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an adhesive tape. More specifically, the present invention relates to an adhesive tape that is difficult to break even when the adhesive tape is used, especially during high-speed WJ impact withdrawal when the withdrawal angle is large.

[Prior art] A so-called polyester adhesive tape, which has an adhesive layer on one or both sides of a polyethylene terephthalate film, is
It is widely used for general industrial purposes and electrical insulation. The reason is that polyester film has mechanical strength, dimensional stability, and abrasion resistance.

This is because its properties such as chemical resistance, water resistance, transparency, and electrical insulation are much superior to other synthetic resin films such as polypropylene and polyvinyl chloride, and cellophane. However, even seemingly transparent polyester films have drawbacks.

When using a tape that is wound in concentric circles, such as cellophane tape, the tape can be easily removed by increasing the pulling angle of the tape (180° peeling in extreme cases) and performing a high-speed impact pulling operation. Cut into. In particular, when the adhesive strength is increased so that a large force is applied during peeling, there is a marked tendency to easily break the adhesive. This cutting phenomenon cannot be expected from the general idea that polyester film is strong, but when the fracture surface is observed in detail using a scanning electron microscope, it is found that layered fracture occurs in the plane or diagonal direction of the polyester film. This is thought to be the cause of the amputation. This is probably because the strength in the thickness direction of the polyester film is lowered due to the so-called plane orientation phenomenon in which specific planes of crystals are oriented in a certain direction due to biaxial stretching.

Furthermore, other characteristics of market demands for adhesive tapes include:
There has been an increase in adhesive strength, and the above improvements have become an essential condition to meet this demand. As the adhesive strength increases, strain concentrates on the base film when the tape is pulled out, and the demand for impact resistance of the base film has become even more desirable.

By the way, polyester films are generally required to have good winding properties and processability, and for this purpose, it is necessary that the polyester film has a low coefficient of friction. Conventionally,
As a technique for reducing the coefficient of friction of a film, protrusions are imposed on the surface of the film by stretching a polymer containing inorganic particles or a polymer containing insoluble catalyst residue particles. It has become customary.

Voids are usually formed around these particles in the stretched film, and these voids are one of the causes of laminar fracture, which is the cause of breakage when the tape is drawn out.

That is, the breakage of the polyester adhesive tape due to laminar destruction occurs due to the high plane orientation of the polyester film and the voids around the inorganic particles added or generated in the film. This plane orientation can be reduced by lowering the stretching ratio during polyester film production, but this method reduces the tensile strength of the polyester film,
This results in increased thickness unevenness, etc. It is also possible to improve the cutting caused by laminar breakage by reducing the amount of inorganic particles in the film, but this method reduces the windability of the film.

[Objective of the Invention] = 3. The object of the present invention is to solve the above-mentioned problems of the prior art, and to prevent the adhesive tape from breaking even when the tape is pulled out at a large angle and subjected to high-speed impact pulling operation. I3': To provide an excellent adhesive tape.

[Structures and Effects of the Invention] According to the present invention, an adhesive tape comprising a biaxially oriented polyester film coated with an adhesive layer on at least one side, wherein the polyester film has a structure in the polyester. Composition of 80% by weight or more of the unit is CH3
・Silicone resin fine particles made of trifunctional organosiloxane expressed by 5tO1/2 and having a volume shape coefficient of 0.20 to 0.52 and an average particle size of 0.1 to 4 μm are mixed into 0.03 to 1.0 μm. This is achieved by an adhesive tape characterized by a film containing 0% by weight.

In the present invention, poly(1-styrene) is a polyester containing aromatic dicarboxylic acid as the main acid component and aliphatic glycol as the main glycol component.

Such polyesters are substantially linear and have film forming properties, particularly by melt molding. Examples of aromatic dicarboxylic acids include terephthalic acid,
Naphthalene dicarboxylic acid, isophthalic acid, dipheninoxyethane dicarboxylic acid.

Diphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid.

Examples include diphenylketone dicarboxylic acid and anthracene dicarboxylic acid. Examples of aliphatic glycols include polymethylene glycols having 2 to 10 carbon atoms such as ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, and decamethylene glycol, and fats such as cyclohexane dimetatool. Examples include cyclic diols.

In the present invention, polyesters containing, for example, alkylene terephthalate and/or alkylene naphthalate as main constituents are preferably used.

Among such polyesters, for example, not only polyethylene terephthalate and polyethylene-2,6-naphthalate, but also terephthalic acid and/or 2,6-naphthalene dicarboxylic acid account for 80 mol% or more of the total dicarboxylic acid component; A copolymer in which 80 moles or more of the glycol component is ethylene glycol is preferred. In this case, up to 20 mol% of the dicarboxylic acid in the total acid component can be the above-mentioned aromatic dicarboxylic acids, and also include, for example, aliphatic dicarboxylic acids such as adipic acid and cepatic acid; It can be a cyclic dicarboxylic acid or the like. In addition, 20% of the total glycol component
Up to mol% can be of the above glycols other than ethylene glycol, or for example hydroquinone,
Aromatic diols such as resorcinol, 2,2-bis(4-hydroxyphenyl)propane; aliphatic diols containing aromatics such as 1,4-dihydroxymethylbenzene; polyethylene glycol, polypropylene glycol, polytetramethylene glycol It can also be a polyalkylene glycol (polyoxyalkylene glycol) such as.

Furthermore, in the polyester used in the present invention, a component derived from an oxycarboxylic acid such as an aromatic oxyacid such as hydroxybenzoic acid; an aliphatic oxyacid such as ω-hydroxycaproic acid, a dicarboxylic acid component and an oxycarboxylic acid component. Those copolymerized or combined in an amount of 20 mol % or less based on the total amount of components are also included.

Furthermore, the polyester in the present invention contains a substantially linear amount of polycarboxylic acid or polyhydroxy compound, such as trimellitic acid, pentamellitic acid, etc., in an amount of 2 mol% or less based on the total acid component. It also includes those copolymerized with erythritol.

The above polyester is known per se, and can be produced by a method known per se.

The above polyester has an intrinsic viscosity of about 0.4 measured as a solution in 0-chlorophenol at 35°C.
~0.9 is preferred.

The biaxially oriented polyester film of the present invention has many fine protrusions on its surface.

According to the present invention, those many fine protrusions are derived from a large number of silicone resin fine particles dispersed and contained in the polyester.

Polyester containing dispersed silicone resin particles can be produced at any time during the reaction to form polyester, for example, during the transesterification reaction or polycondensation reaction when using the transesterification method, or at any time during the polycondensation reaction when using the direct polymerization method. It can be produced by adding silicone resin microparticles (preferably as a slurry in glycol) to the reaction system. Preferably, silicone resin fine particles are added to the reaction system at the beginning of the polycondensation reaction, for example, until the intrinsic viscosity reaches about 0.3.

In the present invention, the silicone resin fine particles contained in the polyester have a composition of 80% by weight or more of the structural units of CH3.
・Made of trifunctional organopolysiloxane expressed by 5iOy2, with a volume shape coefficient of 0.20
~0.52 and an average particle size of 0.1 to 4 μm. The above structural unit composition CHa ・Si
O3/2 is expressed by the unit structural formula:
It is an organopolysiloxane with a three-dimensional bond structure represented by Oy2)n. Here, the above n represents the degree of polymerization,
100 or more is preferable. Other components include bifunctional organopolysiloxane or other trifunctional organosiloxane derivatives.

The silicone resin fine particles have excellent lubricity, have a lower specific gravity than inorganic inert fine particles, and have better heat resistance than organic fine particles, and are insoluble in organic solvents, It also has the characteristic of being non-melting. Furthermore, silicone resin fine particles exhibit excellent affinity for polyester.

The silicone resin fine particles used in the present invention have an average particle size of 0.
It is 1 to 4 μm, preferably 0.1 to 2 μm, and more preferably 0.8 to 2 μm. Average particle size is 0.1μm
If it is less than 4 μm, the effect of improving slippage 1j1 and processing suitability (winding property, etc.) will be insufficient, while if it exceeds 4 μm, the cut resistance will be insufficient, which is not preferable.

Note that the average particle diameter referred to herein is expressed as the diameter at the cumulative 50% point of the equivalent spherical diameter particle size distribution calculated based on Stokes' equation.

In order to obtain particles with a predetermined average particle size, pulverization treatment or classification operation of commercially available silicone resin fine particles may be employed.

Furthermore, the silicone resin fine particles have a volume shape coefficient of 0.
20 to 0.52. By providing these characteristics, the biaxially oriented polyester film has extremely excellent sliding properties, and the lamellar fracture of the biaxially oriented polynisder film is improved due to the affinity of the silicone resin particles for polyester. be done.

Generally, polyester and inorganic fine particles have no affinity. Therefore, when a melt-formed unstretched polyester film is biaxially stretched, peeling occurs at the boundary between the particles and the polyester, and voids are formed around the fine particles. These voids are more likely to occur as the fine particles are larger, as the shape is closer to a spherical shape, as the fine particles become a single particle and are less likely to deform, and as the unstretched film is stretched at a higher stretching area ratio and as the temperature is lower. growing. The larger the voids become, the looser the shape of the protrusions becomes, increasing the coefficient of friction and causing deterioration in laminar fracture resistance.

As described above, in the case of conventional inorganic inert lubricants, the amount of voids around the lubricant is quite large, and in high-strength polyester films, these voids become even larger, and as a result, the delamination property of the biaxially stretched film becomes remarkable. Adhesive tapes using such polyester films frequently break during high-speed drawing.

However, since the silicone resin fine particles in the present invention have an affinity for polyester, no voids are formed, or even if voids are formed, they are very small. Therefore, the adhesive tape based on the biaxially oriented polyester film of the present invention is unlikely to be cut due to laminar destruction during high-speed drawing.

In the present invention, the amount of silicone resin fine particles added must be 0.03 to 1.0% by weight, preferably 0.1 to 0.5% by weight, based on the polyester. If the amount added is less than 0.03% by weight, the effect of improving winding properties and processability will be insufficient, while if it exceeds 1.0% by weight, the cut resistance will decrease, which is not preferred.

The silicone resin fine particles are not limited in any way in terms of their manufacturing method or other aspects as long as they satisfy the above conditions.

In the biaxially oriented polyester film of the present invention, the surface of the film is ion-etched to expose the silicone resin fine particles in the film, and when the surface is observed with a scanning electron microscope, most of the particles in the biaxially oriented polyester film are No voids are observed around the silicone resin particles. This is surprising when compared to the void generation situation in the case of inorganic fine particles such as kaolin. Note that this can also be easily observed by transmission observation using an optical microscope.

Since voids are not generated in this manner, a biaxially oriented polyester film having excellent laminar fracture resistance can be obtained. In particular, there are almost no or no voids even in a high-strength polyester film that has been stretched at a high magnification and has an increased Young's modulus.

The biaxially oriented polyester film of the present invention can be produced according to conventional methods for producing biaxially oriented films.

For example, by melt-casting polyester containing silicone resin particles to form an amorphous unstretched film, then stretching the unstretched film in biaxial directions, heat setting, and if necessary, relaxing heat treatment. Manufactured. that time,
The film surface characteristics are determined by the shape and size of the silicone resin particles.

Since it varies depending on the amount and the stretching conditions, the stretching conditions are appropriately selected from conventional stretching conditions. Void again.

Density, heat shrinkage rate, etc. also include stretching, temperature during heat treatment, and A8 rate.

Since it changes depending on the speed, etc., conditions that satisfy these characteristics at the same time are determined. For example, the stretching temperature is such that the degree of first-stage stretching (for example, longitudinal stretching temperature: T+) is (Tg-10)
(Tg+45)"C (where Tg is the glass transition temperature of polyester), the second-stage stretching temperature (for example, the transverse stretching temperature 2 T2) is from (T+ +is) to (T+ -1
-40) It is recommended to select from the range of ℃. Further, the stretching ratio is preferably selected from a range in which the uniaxial stretching ratio is 2.5 or more, particularly 3 times or more, and the area magnification is 8 times or more, especially 10 times or more. Furthermore, the heat setting temperature is 180~2
It is preferable to select from the range of 50°C, more preferably from 200 to 230°C.

In the present invention, the adhesive layer coated on at least one side of the above biaxially oriented polyester film can be formed using a conventional adhesive tape production method and adhesive. As the adhesive, for example, a rubber-based, vinyl ether-based, acrylic polymer, etc. may be used, and a hot melt type adhesive may be used. The coating method may be to apply and dry an organic solvent or emulsion, or to apply a material such as ethylene-vinyl acetate copolymer by a melt extrusion method and use this as an adhesive. The adhesive may be applied to one side, but when producing a double-sided adhesive tape, it may be applied to both sides. An adhesive may be applied to one side, and a silicone-based mold release agent may be applied to the other side. However, the adhesive type, application method, etc. are not limited to these.

The pressure-sensitive adhesive tape of the present invention may be provided with other layers such as a colorant layer, if desired.

Various physical property values and characteristics in the present invention were measured and defined as follows.

(1) Average particle size Shimadzu CP-50 Centrifugal Particle Size Analyzer (CentrifugalP
arti(ileS iZe A analyzer
). From the cumulative curve of particles of each particle size and their abundance calculated based on the obtained stretching sedimentation curve, 5
The particle size corresponding to 0 mass percent was read, and this value was taken as the above-mentioned average particle size (see "Particle Size Measurement Technique", published by Nikkan Kogyo Shimbun, 1975, pp. 1, 242-247).

(2) Film surface roughness Ra) Center line average roughness: This is a value defined in JIS-30601 as Ra (unit: μm).

In this invention, ■ Koita Research Institute's stylus type surface roughness meter (SLJR)
FCORDER5E-30G), stylus radius: 2
μm, measurement pressure: 0.03g, cutoff value: 0.2
A film surface roughness curve is drawn under the conditions of 5 problems, a part of the measuring length is extracted from the film surface roughness curve in the direction of its center line, the center line of this sampled part is taken as the X axis, and the longitudinal magnification is With the direction of Y axis, the roughness curve is Y=f(x)
When expressed as , the value given by the following formula (Ra: μT
rL) is defined as the film surface roughness.

Ra = 1/L, /" If (x) ldxθ Five measurements were taken with the reference length as 2.5#, and Ra was expressed as the average value of the four measurements, excluding one from the one with the largest value.

(3) Volume shape factor f A photograph of the silicone resin microparticles was taken using a scanning electron microscope, and the maximum diameter of the projected surface was determined using an image analysis processing device Luzex 500 (manufactured by Nippon Regulator). Calculate using the following formula using the volume.

f = V/D3 In the formula, ■ represents the volume of the particle (μTrL3), and D represents the maximum diameter of the projection surface (μm).

(4) The surface of the void film is ion-etched to expose the fine particles in the film, and aluminum is uniformly vacuum-deposited on the surface of the film to a thickness of 400 to 500 mm or less. The surface was observed at a magnification of 5,000 times, and the long axis of the solid fine particles and the long axis of the voids were measured.The ratio of void long axis)/(solid fine particle long axis) was defined as the void ratio. The number of measurements was 40, and the average value was expressed. Ion etching is performed using, for example, JFC-1 manufactured by JEOL Ltd.
Using 100 type ion sputtering equipment, 500V
, 12.5TrL8 for 15 minutes. The vacuum level is 10'Torr.

(5) Haze (haze) According to JIS-674, the haze of the film was determined using an integrating sphere HTR meter manufactured by Nippon Seimitsu Kogaku Co., Ltd.

(6) Cutting properties of the tape by pulling out the adhesive tape wound in concentric circles was manually subjected to high-speed impact peeling 20 times in the opposite direction to the pulling direction (180° peeling), and the number of breaks was as follows: Evaluate as follows.

0 to 2 times: O (very good) 3 to 6 times: △ (slightly good) 7 times or more: X (poor, equivalent to the current level) (7) Windability In the manufacturing process of biaxially oriented polyester film, is rolled up into a roll of 4000 m in width with a width of 5000 s, the appearance of this roll is inspected in detail, the number of diseased protrusions with a major diameter of 2 am or more is counted, and the results are rated as follows.

0-2: 0 3-5: Δ 6 or more: × [Example] The present invention will be explained in more detail with reference to Examples.

Reference Example 1.2 Dimethyl terephthalate and ethylene glycol, manganese acetate as a transesterification catalyst, antimony trioxide as a polymerization catalyst, phosphorous acid as a stabilizer, and a lubricant with an average particle diameter of 1.2 μm 1 Volume shape coefficient o, oe Polyethylene terephthalate having an intrinsic viscosity of 0.62 was obtained by polymerization using a conventional method using kaolin. The amounts of Naori-Olin added were 0.1° and 0.03% by weight, respectively.

After drying these polyethylene terephthalate (hereinafter abbreviated as PET) pellets at 170°C for 3 hours, they are fed to an extruder hopper, melted at a melting height of 280 to 300°C, and passed through a slit-shaped die containing 1# of the molten polymer to give a surface finish of 0. The film was formed and extruded on a rotating cooling drum with a temperature of about .3S and a surface temperature of 20°C to obtain an unstretched film of 300 μm.

The unstretched film thus obtained was preheated at 75°C, and further rolled between low speed and high speed rolls from 15 cm above to 90 °C.
It was heated with a single IR heater with a surface temperature of 0°C, stretched 3.5 times in the machine direction, and then rapidly cooled, then fed to a stenter and stretched 3.7 times in the cross direction at 105°C. The obtained biaxially stretched film was heat set at a temperature of 205° C. for 5 seconds to obtain a heat set biaxially stretched film with a thickness of 23 μm. The resulting film had a void ratio of 1.7.

The properties of this film are shown in Table 1.

Reference Examples 3 to 10 Instead of kaolin, silicone resin fine particles (Toshiba product name
Pellets of polyethylene terephthalate were obtained in the same manner as in Comparative Example 1.2, except that fine particles prepared using C99-301 and -501 were used. A heat-set biaxially oriented film with a thickness of 23 μm was obtained in the same manner as in Comparative Example 1.2 except that the pellets were used. The properties of this film are shown in Table 1.

20 All of the films obtained in the Reference Examples were of excellent quality.

Examples 1 to 7 and Comparative Examples 1 to 3 After each side of the films obtained in Reference Examples 1 to 10 was subjected to corona treatment, a toluene solution (adhesive After drying in hot air at 90° C., the tape was slit to a width of 19 mm to evaluate cuttability in a form similar to commercially available cellophane tape. The results are shown in Table 1.

As is clear from this table, tapes that satisfy the conditions of the present invention have a small number of tape pull-out cuts and excellent winding properties.

Procedural amendment May/7th, 1986

Claims (1)

[Claims] In an adhesive tape formed by coating an adhesive layer on at least one side of a biaxially oriented polyester film, the polyester film contains 80% by weight of the structural units in the polyester.
The above composition is composed of trifunctional organosiloxane represented by CH_3・SiO_y_2, and has a volume shape coefficient of 0.20 to 0.52 and an average particle size of 0.1 to 4 μm.
An adhesive tape characterized in that it is a film containing 0.03 to 1.0% by weight of silicone resin fine particles.