JPH01266177A - Film for heat-resistant pressure-sensitive adhesive tape - Google Patents

Abstract

PURPOSE:To prepare a heat-resistant pressure-sensitive adhesive type which is excellent in the workability, travelling and electric characteristics, particularly in the heat resistance, by providing, through coating, a pressure-sensitive adhesive layer on at least one surface of a biaxially orientated thermoplastic polyether ketone resin film having particular properties. CONSTITUTION:This pressure-sensitive tape comprises a pressure-sensitive adhesive layer provided on at least one surface of a film by coating. Said film is a biaxially orientated thermoplastic polyether ketone resin film and exhibits a heat shrinkage of 3.0% or less at 150 deg.C and an elongation at break of 10% or more after heating at 280 deg.C for 500hr. It is pref. that the refractive index in the thicknesswise direction, F-5 value and surface roughness of the film be 1.64 or less, 11kg/mm<2> or more and 0.005-0.1mum, respectively. The thermoplastic polyether ketone resin may be blended with other resins, such as polyarylene polyether, polysulfone, polyarylate, polyester or polycarbonate, for the purpose of improving the flowability etc. and further may be blended with additives such as stabilizers, antioxidants or ultraviolet absorbers.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a film for heat-resistant adhesive tape.

More specifically, the present invention relates to a film for heat-resistant adhesive tape that has excellent workability, runnability, electrical properties, and particularly heat resistance.

(Prior art) Biaxially oriented polyethylene terephthalate film has excellent mechanical properties, electrical properties, heat resistance, chemical resistance, etc., so it can be coated with an adhesive layer on one or both sides.
As a so-called polyester adhesive tape, -S industrial use,
Widely used for electrical insulation.

However, in recent years, the characteristics required for adhesive tapes have increased, and there are limits to the characteristics of biaxially oriented polyethylene terephthalate films, so there is a demand for films with even more excellent characteristics. For example, biaxially oriented polyethylene terephthalate film has long-term heat resistance of 8 types (long-term heat resistance temperature: 120'C> to B type (130°C)), and when used as a late-end material for electrical equipment or as a wire coating material,
This long-term heat resistance poses a problem in that miniaturization of electrical equipment is restricted. Furthermore, when a polyester adhesive tape is used in contact with solder, solder heat resistance becomes a problem, and its development is limited. For these reasons, there is a demand for films with even better heat resistance.

On the other hand, polyetherketone is known as a crystalline thermoplastic polymer that is tough and has excellent heat resistance (Japanese Patent Publication No. 1983-
32642, Japanese Patent Publication No. 61-10486), this film has been studied and proposed. For example, JP-A-57-
Publication No. 137116 states that polyetherketone is expected to be used in fields that take advantage of its heat resistance, such as insulating films for motors, insulating films for transformers, insulating films for capacitors, and flexible printed circuit boards. A method of producing a uniaxially oriented film by a rolling method is described. Also, JP-A-61-37
Publication No. 419 describes that a biaxially oriented thermoplastic polyetherketone film is suitable for the field of electrical and electronic parts such as capacitors, wire coatings, and flexible printed circuit boards, and precision parts such as recording media. ing.

(Problem to be solved by the invention) Therefore, when we created an adhesive tape by using a conventionally known thermoplastic polyetherketone resin instead of the polyethylene terephthalate film of the conventional polyester adhesive tape, we found the following new adhesive tape. A problem arises.

In other words, when using a tape that is wound in concentric circles, such as cellophane tape, if the tape is pulled out at a large angle (in extreme cases, 180° peeling is performed), then the tape is Easy to cut. In particular, if the adhesive strength is increased so that a large force is applied during peeling, there is a marked tendency for the adhesive to break easily. This cutting phenomenon cannot be expected from the general idea that thermoplastic polyetherketone resin films are strong, but when the fractured surface was observed in detail using a scanning electron microscope, it was found that the thermoplastic polyetherketone resin film was flat. There are parts where layered destruction occurs in the direction or diagonal direction, and it is presumed that this is the cause of the cutting. This is probably due to the fact that the thermoplastic polyetherketone resin film has a low strength in the thickness direction due to the so-called plane orientation phenomenon in which the specific planes of the crystals are oriented in a certain direction due to biaxial stretching.

Furthermore, another property demanded by the market for adhesive tapes is an increase in adhesive strength, and the above-mentioned improvements are an essential condition for meeting this demand. As the adhesive strength increases, distortion concentrates on the base film when the tape is pulled out.
The impact resistance strength of the base film is becoming more and more desirable.

By the way, thermoplastic polyetherketone resin films are required to have good winding properties and processability, and for this purpose, it is necessary that the thermoplastic polyetherketone resin has a low coefficient of friction. Conventionally, techniques for reducing the coefficient of friction of a film include adding protrusions to the surface of the film by forming a stretched film using a polymer to which inorganic particles have been added or a polymer in which insoluble catalyst residue particles have been generated. 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.

In other words, the breakage of thermoplastic polyetherketone resin adhesive tape due to layered fracture occurs due to the high plane orientation of the thermoplastic polyetherketone resin film and the voids around the inorganic particles added or generated in the film. do. This plane orientation can be reduced by lowering the stretching ratio during production of the thermoplastic polyetherketone resin film, but this method results in a decrease in the tensile strength of the thermoplastic polyetherketone resin film, an increase in 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.

An object of the present invention is to provide a biaxially oriented thermoplastic polyetherketone resin film for use in adhesive tapes, which has a flat surface, has excellent slip properties, running durability, insulation properties, etc., and has excellent heat resistance.

Another object of the present invention is to solve the above-mentioned problems of the prior art, and to provide an excellent adhesive tape that does not break even when the tape is pulled out at a large angle and subjected to high-speed impact pulling operations. An object of the present invention is to provide a biaxially oriented thermoplastic polyetherketone resin film.

(Means for Solving the Problems) According to the present invention, the above object is to provide a film for use as an adhesive tape by coating an adhesive layer on at least one side, wherein the film is made of biaxially oriented thermoplastic polyether. It is a ketone resin film and has a heat shrinkage rate of 3 at 150℃.
．． A film for a heat-resistant adhesive tape characterized by having a breaking elongation of 0% or less and a breaking elongation of 10% or more after heating at 280°C for 500 hours, furthermore, a film having a refractive index in the thickness direction of 1
．． 64 or less, an F-5 value of 11 kg/mm'' or more, and a film surface roughness of 0.005 to 0.1 μm.

The thermoplastic polyetherketone resin in the present invention is a structural unit or a polymer consisting of this unit and other structural units. Examples of other fi4 component units include the following. In the above structural unit, A is a direct bond, oxygen, -3
O□-1-〇〇□- or a divalent lower aliphatic hydrocarbon group, Q and Q' may be the same or different and are -CO- or -802-, and n is 0 Or l. These polymers are disclosed in Japanese Patent Publication No. 60-32642,
Japanese Patent Publication No. 61-10486, Japanese Patent Publication No. 57-1371
It is described in Publication No. 16, etc.

Thermoplastic polyetherketone resins contain polyarylene polyether, polysulfone,
Resins such as polyarylate, polyester, and polycarbonate may be blended, and stabilizers, antioxidants,
Additives such as ultraviolet absorbers may also be included.

As mentioned above, thermoplastic polyetherketone resins are known per se, and can be produced by methods known per se.

The above thermoplastic polyetherketone resin has an apparent melt viscosity at a temperature of 380°C and an apparent shear rate of 200°C and 5ec.
-' is preferably in the range of 500 poise to 1000 poise, more preferably 1000 poise to 5000 poise, from the viewpoint of film formability and film properties.

The biaxially oriented polyetherketone resin film of the present invention is
It is necessary that the transverse heat shrinkage rate when heat treated at 150° C. for 30 minutes is 3.0% or less, preferably 0.5% or less, and more preferably 0.3% or less. If the heat shrinkage rate of the film exceeds 3.0%, adhesive application,
A problem arises in that it shrinks significantly during drying and cannot withstand use as a tape.

Further, the film in the present invention has a temperature of 50°C at 280'C.
It is necessary that the elongation at break when heated for 0 hours is 10% or more. If this elongation at break is less than 10%, it will become brittle and easily break when external force is applied.
A problem arises that there is a practical problem.

Furthermore, the film for heat-resistant adhesive tape of the present invention has a refractive index in the thickness direction of the film of 1.64 or less, preferably 1.
662 or less, more preferably 1.61 or less, F-5 value for force kg/am” or more, preferably 12 kg/Tsuru2
above, more preferably 13 kg/am'' or above, and the film surface roughness is 0.005 to 0.1 μm, preferably 0.
0.007 to 0.07 μm, more preferably 0.01 to 0.07 μm.
It is desirable that the thickness is 0.05 μm. If the refractive index in the thickness direction of the film is greater than 1°64, the breaking strength will be low, resulting in insufficient strength as an adhesive tape, and the F-5 value will be 11 kg.
/me'', the adhesive tape easily deforms.

Furthermore, if the roughness of the film surface is too small, the coefficient of friction of the film will increase, resulting in poor winding properties and processability. Conversely, if the surface roughness is too large, the dielectric breakdown voltage will decrease.

The thermoplastic polyetherketone resin film of the present invention is
For example, a thermoplastic polyetherketone resin is melt-extruded at a temperature of (Tm+30)'C to Tm+90)°C (Tm is the melting point) to obtain an unstretched film, and the unstretched film is uniaxially (vertical or transverse) (Tg-10) ~ (T
g +45) Stretched at a temperature of 1.5 times or more, particularly 2.5 times or more, at a temperature of "C" (Tg: glass transition temperature of polyetherketone resin), and then stretched in a direction perpendicular to the above stretching direction (- When the first stage stretching is in the vertical direction, the second stage stretching is in the horizontal direction) from (Tg + 10) to (T g +
40) It can be produced by stretching at a temperature of 2.5 to 5.0 times. In this case, the area stretching ratio is preferably 4 times or more, more preferably 6 times or more. The stretching means may be either simultaneous two-wheel stretching or sequential two-wheel stretching. Furthermore, the film subjected to two-wheel stretching has (T g +70)'
Heat setting may be performed at a temperature of C to Tm"C. For example, for polyether ether ketone film, the temperature is 250 to
It is preferable to heat set at 350°C. The heat setting time is, for example, 1-120 seconds.

The thickness of the thermoplastic polyetherketone resin film of the present invention is preferably 1 to 250 μm, more preferably 2 to 125 μm, particularly 3.5 to 75 μrn.

As a means of adjusting the surface roughness of the film within the above range, substantially inert solid particles may be uniformly dispersed in the thermoplastic polyetherketone resin in the film, and the particle size and content thereof may be adjusted. . The inert solid particles may be externally added particles or internal particles, and may also be, for example, metal salts of organic acids, inorganic substances, special resins, etc. Preferred inert solid particles include: -calcium carbonate, -silicon dioxide (including hydrates, diatomaceous earth, silica sand, quartz, etc.), -alumina, and -silicates containing 30% by weight or more of SiO□. (For example, amorphous or crystalline clay minerals, aluminosilicate compounds (including calcined materials and hydrates), warm asbestos, zircon, fly ash, etc.), ■Oxides of Mg, Zn, Zr, and T1, ■Ca and Ba sulfate, ■Li, Na
and Ca phosphates (including monohydrogen salts and dihydrogen salts), ■
Benbrozoates of Li, Na and K, Terephthalates of Ca, Ba5Zn and Mn, [Phase] M g % Ca S
B a SZ n sCd, P b −S r %
M n ,, Fe % Titanate of Co and Ni, ■ Chromate of Ba and Pb, ■ Carbon (e.g. carbon black, graphite, etc.), ■ Glass (e.g. glass powder, glass peas, etc.) [Phase] MgC0 , , [phase] fluorite, [phase] ZnS, and (2) silicone resin are exemplified. Preferred examples include anhydrous silicic acid, hydrated silicic acid, aluminum oxide, aluminum (including calcined products, hydrates, etc.) lithium phosphate, trilithium phosphate, sodium phosphate, calcium phosphate, barium sulfate, titanium oxide, and ammonium phosphate. lithium oxide, double salts of these compounds (including hydrates), glass powder, clay (including kaolin, bentonite, clay, etc.), talc,
Examples include diatomaceous earth and silicone resin. The average particle size of these inert solid particles is usually 0.01 to 3 μm, preferably 0.05 to 2 μm, and more preferably 0.05 to 2 μm.
．． It is 1 to 1.5 μm. Further, the content of these inert solid particles is usually 0.005 to 1% by weight based on the thermoplastic polyetherketone resin, but may be 0.01 to 1% by weight, and more preferably 0.01 to 1% by weight. O1 to 0.5% by weight, especially 0.05 to
0.3% by weight is preferred.

In addition, among the above inert solid particles, the average particle size is 0.0
5 to 4 pm, particle size ratio (major axis/breadth axis) is 1. Fine spherical silica particles having a particle diameter of 0 to 1.2 are mixed alone or with other inert solid particles mentioned above so that the content is 0.01 to 3.0% by weight, and then added to a thermoplastic polyetherketone resin. When dispersed, or the average particle size is 0.01 to 4. um, f
=V/D' (where ■ is the average volume of particles (μm3
), [) indicates the average maximum particle diameter (μm) of the particles) The volume shape coefficient <r> is 0.4 to π/6,
Silicone resin fine particles represented by the general formula RX S i O2-X/2 (where R is a hydrocarbon group having 1 to 7 carbon atoms, and X is 1 to 1.2) have a content of o, oos to 3
．． When dispersed in a thermoplastic polyetherketone resin either alone or mixed with the other inert solid particles mentioned above, the concentration of spherical silica fine particles, silicone resin fine particles, and polyetherketone resin is 0% by weight. Due to its high affinity, voids are less likely to occur around the particles when biaxially oriented, and it is possible to produce a film with good electrical insulation and improved cutting resistance due to layered fracture, making it particularly suitable. be. In this case, it is preferable that the spherical silica fine particles be substantially spherical, have a sharp particle size distribution, and be close to monodisperse, and there are no limitations on the manufacturing method or other aspects. In particular, it is desirable that the relative standard deviation expressed by the following formula is 0.5 or less.

Relative standard difference - Hydrolyzed silica (S i (OH) 4 ) monodisperse method is created from the hydrolysis of (S i (OCz Hs) a ), and this hydrated silica monodisperse method is further dehydrated to form silica bonds ( =Si-0-3i] can be produced by three-dimensional growth (Journal of the Chemical Society of Japan 81, N09,
P, 1503).

S i (OC2Hs) 4 +4Hz O→S
i (OH) s +4 Cz Hs 0H=Si
-OH+HO-3i Mi→Mi S i -0-3i =+H20 On the other hand, it is preferable that the silicone resin fine particles are substantially spherical, have a sharp particle size distribution, and are close to monodisperse. It is not limited. In particular, the viscosity distribution ratio (γ) expressed by the following formula is 1 to
1.4 is desirable.

Spherical silicone resin particles are The following formula (A) It has the composition represented by.

R in the above formula (A) is a hydrocarbon group having 1 to 7 carbon atoms, and is preferably an alkyl group having 1 to 7 carbon atoms, a phenyl group, or a tolyl group. The alkyl group having 1 to 7 carbon atoms may be linear or branched, such as methyl, ethyl, n-propyl, 1so-propyl, n-
Examples include butyl, 1so-butyl, ter L-butyl, n-pentyl, n-heptyl, and the like.

Among these, R is preferably methyl and phenyl, with methyl being particularly preferred.

X in the above formula (A) is a number l-1,2.

When X is 1 in the above formula (A), the above formula (A)
can be represented by the following formula (A)-1 R3jO+, s... (A)-1 [Here, the definition of R is the same as above].

The composition of the above formula (A)-1 originates from the following structural part in the three-dimensional polymer structure of silicone resin: -0-3i-0-.

In addition, when X is 1.2 in the above formula (A), the above formula (A) becomes the following formula (8)-2 R,, z S i O,, a ...... (A
)-2 (here, the definition of R is the same as above).

The composition of <A>-2 above is the structure 0.8 of (A)-1 above.
mol and 0.2 mol of the structure represented by the following formula (A)' R, SiO... (A)' [Here, the definition of R is the same as above] be able to.

The above formula (A)' originates from the following structural part in the three-dimensional polymer chain of silicone resin: -0-3i-0-.

As understood from the above explanation, the composition of the above formula (A) may consist essentially only of the structure of the above formula (A)-1, or the structure of the above formula (A)-1 and the above formula ( A!-
It can be seen that the structures of No. 2 coexist in a state where they are randomly bonded at an appropriate ratio.

The spherical silicone resin particles preferably have the above formula (A)
, X has a value between 1 and 1.1.

These silicone resin particles can be produced, for example, by hydrolyzing and condensing a fractionated water decomposition condensate of the following formula in the presence of ammonia or an amine such as methylamine, dimethylamine, ethylenediamine, etc., with stirring. According to the above method using the above starting material, silicone resin particles having the composition represented by the above formula (A)-1 can be produced.

Rz S i (OR') z [Here, the definitions of R and R' are the same. ] By using the dialkoxysilane represented by the above together with the above trialkoxysilane and following the above method, silicone resin particles having the composition represented by the above formula (A)-2 can be produced.

In the present invention, the adhesive layer coated on at least one side of the biaxially oriented thermoplastic polyetherketone resin film can be formed using a conventional adhesive tape production method and adhesive.

As the adhesive, for example, a rubber-based, vinyl ether-based, or acrylic polymer may be used (or a hot-melt adhesive may be used. In particular, an adhesive having excellent heat resistance may be appropriately selected. The coating method may be a method such as coating and drying in a solvent or emulsion, or a method such as coating with a melt extrusion method such as ethylene-vinyl acetate copolymer and using this as an adhesive. The agent may be applied to one side, but if you are making a double-sided adhesive tape, it may be applied to both sides. Apply the adhesive to one side and apply a silicone-based mold release agent to the other side. However, the adhesive type and coating method 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 (Centrifugal
Particle 5ise Analyser). From the cumulative curve of particles of each particle size and their abundance calculated based on the obtained stretching sedimentation curve, the particle size corresponding to 50 mass percent was read, and this value was taken as the above average particle size. (“Particle size measurement technology” published by Nikkan Kogyo Shimbun, 1975, p. 5, 242-
247).

(2) Film surface roughness (Ra) Center line average roughness: Ra (unit: μm) JIS-B
This is the value defined in O601.

In this invention, ■Stylus type surface roughness meter (SURF) of Koita Research Institute is used.
CORDER5E-30G), stylus radius = 2μ
m, measurement pressure: 0.03 g, cutoff value: 0.2
A film surface roughness curve is drawn under the condition of 5mm, and a part of the measuring length is extracted from the film surface roughness curve in the direction of its center line. Roughness curve Y=f (
x), it is given by the following formula and the value (Ra: μm
) is defined as the film surface roughness.

Five pieces were measured using a standard length of 2.5 cranes, and Ra was expressed as the average value of the four pieces, excluding one piece from the one with the largest value.

(3) Cut the F-5 value film into a sample with a length of 1011 and a length of 15 (In).
The sample (film) was pulled using an Instron type universal tensile tester at a tension speed of 100 mm/min with a chuck distance of 100 fins and a chart speed of 500 mm/min.
It was calculated by dividing the load at 5% elongation by the initial cross-sectional area from the obtained load-elongation curve.

(4) Marked lines are placed on the heat shrinkage rate measurement sample at approximately 30 ca+ intervals, and heat-treated for a certain period of time in a tension-free state in a heating oven (150°C
It was calculated from the change in sample length after 30 minutes) using the following formula.

Thermal Shrinkage Rate - (5) Heat Deterioration Resistance A gear aging tester is used to heat an untensioned ore at 280° C. for 500 hours, and then measure the dielectric breakdown voltage and elongation at room temperature.

a) Breakdown voltage Implemented according to JIS C2318.

b) Breaking elongation A sample cut to a sample width lO -1 length 1501 m was tested using an Instron-type universal tensile tester under conditions of a tension distance of 100 mm, a tensile speed of 1 ON/min, and a chart speed of 50 mm/min. Pull it. If the original length is lo and the length at break is l, then C(1-11o>/I!o)×100
Expressed in %.

(6) Refractive index Measured using an Atsube refractometer at a light wavelength of 589 nm (center of the NaOD line) and a temperature of 20°C.

(7) Solder heat resistance Judged by the change in appearance after immersion at 250° C. according to JIS C6481.

○: No abnormality Δ: Slight deformation ×: Severe deformation (8) Tape pull-out cutting ability Manually cut the concentrically wound adhesive tape in the opposite direction to the pull-out direction (180°C peeling). High-speed impact peeling is performed 20 times, and the number of breaks is evaluated as follows.

0-2 times 20 (very good) 3 to 6 times: Δ (slightly good) 7 times or more: × (defective, equivalent to current level) (Example) Hereinafter, the present invention will be explained in more detail with reference to Examples.

Examples 1 to 10 Comparative Examples 1 to 2 Inert solid particles shown in Table 1 were mixed with thermoplastic polyetherketone (manufactured by IC Corporation: Polyetheretherketone 380G) in the proportions shown in Table 1, and after blending, An unstretched film was prepared by extruding it at 380°C using an extruder and casting onto a casting drum maintained at a temperature of 80'C, and this was stretched at 160"C at the longitudinal and transverse stretching ratios shown in Table 1. A film with a thickness of 12 μm was obtained by biaxially stretching and further heat-setting at the temperature shown in Table 1 for 30 seconds.

The properties of the obtained film were as shown in Table 1.

A toluene solution of an adhesive containing natural rubber and polyterpene resin as main components (adhesive concentration: 25x4) was applied to one side of the film, and dried in hot air at 120°C to a thickness of approximately 8 μm. After forming the adhesive layer, the tape was slit to a width of 19 mm, rolled up into a form similar to commercially available cellophane tape, and the tape was evaluated for its drawing and cutting properties. The results are also shown in Table 1.

(This page, blank space below) As is clear from the above results, the products of the present invention (Examples 1-10) all have excellent heat deterioration resistance and good solder heat resistance, and when made into adhesive tapes. The draw-cutting property of the is also good, and particularly good results were obtained in Examples 1 to 4 and 6 to 9, but when the heat shrinkage rate at 150°C exceeds 3.0% (Comparative Example 1), Both solder heat resistance and tape draw-out cuttability were poor, and when the elongation at break after heating at 280° C. for 500 hours was less than 10% (Comparative Example 2), the film was easily broken and was not practical.

(Effects of the Invention) According to the present invention, the surface is flat, slipperiness, running durability,
It is possible to provide a biaxially oriented thermoplastic polyetherketone resin film for adhesive tapes that has excellent insulation properties, excellent heat resistance, and does not break when the tape is pulled out when the adhesive tape is used.

Claims (2)

[Claims] (1) In a film to be used as an adhesive tape by coating an adhesive layer on at least one side, the film is a biaxially oriented thermoplastic polyetherketone resin film, and has a heat shrinkage rate at 150°C. A film for a heat-resistant adhesive tape, characterized in that the film has a breaking elongation of 3.0% or less and a breaking elongation of 10% or more after heating at 280° C. for 500 hours. (2) The refractive index in the thickness direction of the film is 1.64 or less, F
2. The film for heat-resistant adhesive tape according to claim 1, having a -5 value of 11 kg/mm^2 or more and a film surface roughness of 0.005 to 0.1 μm.