JPH0971754A - Masking tape or sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a masking tape or sheet for coating which is excellent in capability of following curved adherends, such as the surface of an automotive bumper or a motorcycle tank, provides a distinct border lines in coating work, and has a good straightness. SOLUTION: This tape or sheet comprises a carrier and a self-adhesive layer formed on one side thereof. The carrier is made from a copolymer which has hard segments comprising polypropylene and soft segments comprising a copolymer of ethylene and a monomer copolymerizable therewith.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a masking tape or sheet for painting, and more particularly to a curved surface such as a bumper of an automobile or a tank of a motorcycle.
The present invention relates to a masking tape or sheet useful for line drawing (parting line) during painting work.

[0002]

2. Description of the Related Art When painting automobiles and the like, masking tape for parting is used at the boundary of color, especially on curved or bumpy surfaces like bumpers and motorcycle tanks, A support using soft vinyl chloride having excellent flexibility is often used.

[0003]

As the above-mentioned masking tape, one using soft vinyl chloride as a support has hitherto been used, but one using soft vinyl chloride is burned when it is discarded after use. Then, since chlorine gas is generated, it cannot be incinerated as it is. Therefore, there is a problem that, for example, it is necessary to provide a device for removing chlorine gas in the incinerator. For this reason, conversion to incinerable materials is required.

Polyolefin-based materials can be cited as useful materials as an alternative material for such soft vinyl chloride.
However, in general, a polyolefin-based material has a problem that when it is pulled, a local constriction called "necking" occurs and a straight parting line cannot be obtained, as seen in polyethylene and the like. Further, polypropylene and the like have a drawback that in addition to "necking", the flexibility is low and it is difficult to follow irregularities on the adherend.

For the above reasons, it is difficult to obtain a good parting line on the above-mentioned uneven surface to be adhered by the masking tape using the conventional polyolefin-based support film. It was

An object of the present invention is to solve the above-mentioned problems, and to adhere well to curved adhered surfaces such as bumpers of automobiles and tanks of motorcycles with good followability, and
It is an object of the present invention to provide a masking tape or sheet for painting such that a good parting line can be obtained.

[0007]

The present inventors have succeeded in achieving the above object by the present invention described below, and have completed the present invention. That is, the present invention has the following gist. (1) contains a hard segment and a soft segment,
A masking tape or sheet for painting, characterized in that the hard segment comprises polypropylene, the soft segment comprises ethylene, and a monomer copolymerizable with ethylene, and has an adhesive layer on one surface of a support having a copolymer. , (2) The copolymerizable monomer in the soft segment has the formula CH ₂ ═CHR (where R is a carbon number of 1 to 8).
Which represents an aliphatic group or an aromatic group), and / or a diene, which is a masking tape or sheet for painting according to the above (1), and (3) the soft segment is 100 parts by weight of the hard segment. For 30 to 3
A coating masking tape or sheet according to the above (1) or (2), which is a resin contained in an amount of 00 parts by weight, (4) 150
For coating according to any one of the above (1) to (3), wherein the dimensional change rate of the support after heating at ℃ for 1 hour is 20% or less in at least one of the flow direction and the width direction of the support. The masking tape or sheet, (5) the 10% modulus of the support is 0.3 to 4.0 kgf / mm ² , the above (1) to
(4) The masking tape or sheet for coating according to any one of (4), (6) above, wherein the support according to (1) to (5) above is further laminated with a thermoplastic resin. (Five)
The coating masking tape or sheet according to any one of 1.

The support is composed of a hard segment and a soft segment, the hard segment being polypropylene, the soft segment being ethylene, and a copolymer of ethylene and a monomer copolymerizable with ethylene.

Copolymerizable monomers include those of the formula CH ₂
It is preferable to use at least one of α-olefins and dienes represented by ═CHR (wherein R represents a linear or branched aliphatic group or aromatic group having 1 to 8 carbon atoms).

Examples of the α-olefin include butene-
1, pentene-1, 4-methylpentene-1, hexene-1, octene-1, styrene and the like are exemplified as suitable ones.

Preferred examples of the diene compound include butadiene, 1,4-hexadiene, 1,5-hexadiene, ethylidene, norbornenediene and the like.

It is preferable that the hard segment and the soft segment in the resin are present in a state where the compatibility is good, whereby the tearability and stress relaxation of the film are good, and the processability and the peelability are good. In terms of As the above-described good compatibility, a hard segment and a soft segment are bonded by block copolymerization and exist in the same molecule, or IPN (interpenetrating network; in
terpenetrating polymer network) structure, and a state in which it is present in a state of good compatibility is exemplified.

The content of the soft segment is 30 to 300 parts by weight, preferably 40 to 200 parts by weight, based on 100 parts by weight of the hard segment. When the content of the soft segment is less than 30 parts by weight, the flexibility is lowered and the rubber tends to tear easily, and when it exceeds 300 parts by weight, the influence of rubber elasticity becomes excessive and the workability at the time of peeling is deteriorated. Is not good because it tends to become.

The polymer constituting the hard segment or the soft segment is exemplified by homo, block or random polymers.

The above resin may be mixed with another appropriate resin to obtain desired support characteristics. For example, the elastic modulus of the support can be increased by further mixing the resin having a hard segment and the soft segment as described above with a resin such as polypropylene.

The above resin may include titanium oxide, if necessary.
Inorganic fillers such as zinc oxide, calcium carbonate, amine-based, quinoline-based, hydroquinone-based, phenol-based, phosphite-based antioxidants, antioxidants, salicylic acid derivatives, benzophenone-based, benzotriazole-based, hindered amines One or more of ultraviolet absorbers, lubricants, plasticizers, etc., such as system, may be blended within the range not deviating from the gist of the present invention.

After applying the paint, the masking tape is heated at a temperature of several tens to 200 ° C. in a drying tower. Therefore, it is desirable that this support has a small dimensional change such as contraction / expansion even if it is subjected to heat history. Specifically, the support is heated to 150 ° C.
Flow direction of the support after heating for 1 hour at
Direction) and width direction (hereinafter referred to as TD direction)
The dimensional change rate of at least one of the above is preferably 20% or less, particularly preferably 0 to 10%. If the dimensional change rate exceeds 20%, inconveniences such as terminal floating and defective parting due to contraction of the support tend to occur.

The above-mentioned dimensional change rate is 150 ° C. for a support whose dimensions in MD and TD are measured beforehand.
It is a value obtained by leaving in an oven for 1 hour and heating, and then dividing the difference in size between after heating and before heating by the size before heating.

The above-mentioned support usually has a 10% modulus (pulling speed of 300 mm / min.) At 23 ° C. × 65% RH (relative humidity) from the viewpoints of sticking to curved surface and dimensional stability. Preferably 0.3
To 4.0 kgf / mm ² , particularly preferably 0.8 to ² .
A material in the range of 3 kgf / mm ² is used. If the 10% modulus is less than 0.3 kgf / mm ^2, it is too soft,
The dimensional stability of the tape width due to the tension at the time of sticking is poor, the workability of sticking is poor, and the desired parting-off tends to be unobtainable. If it exceeds 4.0 kgf / mm ² , the required flexibility is obtained. However, it is difficult to attach depending on the curved portion or the uneven portion, and the desired parting-off property tends not to be obtained, which is not good. The 10% modulus is measured according to JISZ-0237 tensile strength and elongation test method at 23 ° C. × 65% RH and the value at 10% elongation is measured.

The support may be further laminated with another thermoplastic resin for improving cuttability, rewindability of the tape, and dimensional stability.

As the thermoplastic resin, polyethylene,
Examples thereof include polyolefins such as polypropylene, ethylene-vinyl acetate copolymer, and ethylene-ethyl acrylate, polyesters, and nylons. Among them, a polyolefin containing 30 parts by weight or more of polypropylene is preferably used from the viewpoint of adhesion to the support.

The pressure-sensitive adhesive forming the pressure-sensitive adhesive layer is as follows:
For example, acrylic adhesive, natural rubber adhesive, SIS
(Styrene isoprene block copolymer: styrene is
oprene block copolymer), SBR (styrene butadiene rubber), or IR (isoprene rubber), PIB (polyisobutylene), IIR (butyl rubber:
isobutylene-isoprenerubber) and other synthetic rubber adhesives,
Alternatively, a mixed system of natural rubber and synthetic rubber may be used. Among them, acrylic adhesives and natural rubber adhesives are preferably used because they have high cohesive properties.

The thickness of the support is usually 60 to 200.
μm, the thickness of the pressure-sensitive adhesive layer is usually 5 to 100 μm,
It is preferably 10 to 50 μm. If the film thickness of the pressure-sensitive adhesive layer is less than 5 μm, the target pressure-sensitive adhesive strength cannot be obtained, and “floating” or “peeling” tends to occur on the tape or sheet, while if it exceeds 100 μm, the adhesion becomes insufficient. The force is too strong and the removability tends to deteriorate, which is not good.

The method of applying the adhesive to the support is as follows:
Conventionally commonly used methods can be used, for example, the flow-en method, roll coater method, reverse coater method, doctor blade method, and the like.

[0025]

The present invention will be described more specifically with reference to the following examples. Note that the present invention is not limited to these examples.

Example 1 55 parts by weight of a hard segment made of polypropylene
And a soft segment consisting of ethylene-propylene copolymer
And a resin having 45 parts by weight of the ment (trade name KS-02
1: Highmont MFR (melt flow rate),
Density 0.7g / cm^Three) In 70 parts by weight, the density is 0.92
4g / cm^ThreeLow density polyethylene (MFR1.
5) Extrude a mixture of 30 parts by weight to give a thickness
A support having a thickness of 100 μm was prepared. 10% of this support
Modulus is 0.94 kgf / mm ²And is 150
The dimensional change rate after 1 hour at 4 ° C is 4% in the MD direction,
It was 3% in the TD direction. Then both sides of this support
Corona discharge treatment is applied to the surface, and one side of this treated surface has a thickness of 1
Apply a 5 μm acrylic adhesive and apply a long chain
A backside treatment layer of kill type is formed and a masking tape is produced.
did.

Example 2 The support was made in the same manner as in Example 1 except that the resin constituting the support was changed to a resin containing 80 parts by weight of KS-021 and 20 parts by weight of linear low-density polyethylene. It was made. The 10% modulus of this support is 1.0 kg
f / mm ² , and the dimensional change rate after 1 hour at 150 ° C was 3% in both MD and TD.

Example 3 The resin constituting the support was composed of a resin composition of Example 1 having a thickness A of 70 μm and a carboxyl group-containing modified polyethylene (HIMILAN 1605 MFR2.
A support was prepared in the same manner as in Example 1 except that it had a two-layer laminated structure consisting of 8) and a B layer having a thickness of 30 μm. The 10% modulus of this support is 1.3 kgf /
mm ² and the dimensional change rate after 1 hour at 150 ° C is M
It was 1% in the D direction and 2% in the TD direction.

Comparative Example 1 The resin constituting the support was homopolypropylene (MFR
A support was prepared in the same manner as in Example 1 except that the density was changed to 3.0 g / 10 minutes and the density to 0.90 g / cm ³ .
The 10% modulus of this support is 4.9 kgf / mm
² , and the rate of dimensional change after 1 hour at 150 ° C. was 1% in both MD and TD.

Comparative Example 2 The resin constituting the support was a low density polyethylene (MFR
A support was prepared in the same manner as in Example 1 except that the concentration was changed to 1.5 g / 10 minutes and the density was 0.924 g / cm ³ . The 10% modulus of this support is 0.88 kgf
/ Mm ² , and the rate of dimensional change after 1 hour at 150 ° C is
Measurement was not possible because the contraction of the support was severe.

Experimental Example 1 (Evaluation of Masking Tape) For each of the masking tapes produced in the above Examples 1 to 3 and Comparative Examples 1 to 2, adhesive strength, 100R curved surface sticking property, parting property, and adherend. When evaluated in terms of contamination, Table 1
The result shown in FIG. [Adhesiveness] In accordance with the test method of JISC-2107, temperature 23 ° C., humidity 65% RH, pressure bonding load 2 kg rubber roller 1 reciprocation, pulling speed 300 mm / min. Then, the peeling force was measured. [100R curved surface attachment] 100% on melamine coated plate
I drew a circle of Φ and attached masking tape along the circumference. The criteria for evaluation are that it is possible to attach along the circumference, ○ if there is no wrinkle or lift, ○ if there is some wrinkle or lift, △, if it is difficult to stick along the circumference It was set to x. [Drawability] A masking tape prepared above is attached to a melamine coated plate, and a urethane-based paint (High Urethane No. 5000: manufactured by NOF CORPORATION) diluted with thinner is spray gun to a thickness of 30 μm. And the tape was peeled off after cooling to room temperature. The clarity of the parting line and the linearity of the parting line were visually examined. The criteria for evaluation are as follows: ○ A clear parting line was obtained, △: Some paint penetration into the tape sticking part was seen, △: A parting line was not so clear, Paint paint entering the tape sticking part Was marked, and the parting line was unclear.

[0032]

[Table 1]

[0033]

INDUSTRIAL APPLICABILITY The masking tape or sheet of the present invention is excellent in curved surface followability, particularly when it is attached to an uneven adherend surface such as a bumper of an automobile or a tank of a motorcycle, and has wrinkles, floating, etc. Is less likely to occur. Furthermore, the clarity of the parting line during painting work,
And the linearity is good.

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Claims (6)

[Claims] 1. A pressure-sensitive adhesive is provided on one surface of a support containing a hard segment and a soft segment, wherein the hard segment has polypropylene, the soft segment has ethylene, and a copolymer of ethylene and a copolymerizable monomer. A masking tape or sheet for painting, which has a layer. 2. The copolymerizable monomer in the soft segment has the formula CH ₂ ═CHR (where R is 1 to 8 carbon atoms).
Which represents an aliphatic group or an aromatic group), and / or a diene. 3. The masking tape or sheet for coating according to claim 1, wherein the soft segment is contained in an amount of 30 to 300 parts by weight based on 100 parts by weight of the hard segment. 4. The dimensional change rate of the support after heating at 150 ° C. for 1 hour is 20% or less in at least one of the flow direction and the width direction of the support. Masking tape or sheet for painting. 5. The 10% modulus of the support is from 0.3 to
4.0 kgf / mm ²In any one of Claims 1-4 which is
The masking tape or sheet for painting described. 6. The masking tape or sheet for coating according to claim 1, wherein the support according to any one of claims 1 to 5 is further laminated with a thermoplastic resin.