JP2003342307A - Protective film and its manufacturing process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high quality protective film for a dry film resist. <P>SOLUTION: The protective film is made from a polyethylene film which is obtained by pressurizing ethylene with an ultra high pressure compressor and polymerizing the ethylene at a reaction temperature of 190-300°C under a reaction pressure of ≥167 MPa in the presence of a radical polymerization initiator or by pressurizing ethylene with an ultra high pressure compressor and polymerizing the ethylene at a reaction temperature of 190-300°C in the coexistence of a radical polymerization inhibitor. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a protect film and a method for producing polyethylene for the film.
More specifically, it relates to a contact-type protect film that is directly laminated on the surface of an article to be protected and protects the same, and a method for producing polyethylene for the film. The protect film may also be referred to as a protective film, a masking film or a cover film.

[0002]

2. Description of the Related Art A film resist (also referred to as a dry film resist) for forming a photosensitive layer used as an etching resist when manufacturing a lead frame or a printed wiring board used for mounting a semiconductor integrated circuit is generally a support film (such as polyester). (There are many films consisting of), a positive or negative photosensitive composition is formed, and a protective film for protection is further laminated thereon. As the photosensitive composition, there are known an alkali developing type in which an unexposed area (negative type) or an exposed area (positive type) is removed with an alkaline aqueous solution, and a solvent development type in which an unexposed area (negative type) is removed with an organic solvent. Although the photosensitive composition is solid, it is not a hard solid whose shape does not change but has a certain degree of dimensional deformation.

As an example, a method of manufacturing a printed circuit wiring board and a lead frame by a metal etching method using an alkali developing film resist will be described below.

First, the protect film directly laminated on the film resist is peeled off and laminated (laminated) by a pressure roll so that the film resist contacts a metal substrate such as a copper-clad laminate. Next, the pattern is printed on the film resist on the metal substrate by exposure through a mask on which a desired pattern is drawn. Development is performed with weak alkaline water to form a resist pattern on the metal substrate.
After etching the metal substrate using this resist pattern as a mask, remove the resist pattern with strong alkaline water.
If removed, a printed circuit wiring board and a lead frame are manufactured.

In the laminating step in which the protective film is peeled off and laminated on the metal substrate, air voids are generated at the interface between the metal substrate and the film resist, as pointed out in JP-A-11-153861. Due to the presence of the air voids, there is a possibility that a pattern defect may occur when forming the resist pattern, or a circuit line portion defect portion may occur when the metal substrate is etched.
As described in the publication, air voids are more likely to occur when the film resist as the photosensitive layer is thinner.

In this publication, the determination is made simply by the number of air voids generated, but in short, for example, a drawing pattern of a line having a width of several tens of μm is formed as a circuit substitute, and the pattern in the pattern is formed. Actually, it is better to verify the defect status.

On the other hand, as the material of the protect film, polyester-based materials such as polyethylene terephthalate and polyolefin-based materials such as polypropylene and polyethylene are often used, but in Comparative Example 1 of the publication, the protect film made of polyethylene (the publication). Is referred to as a protective film) is an unfavorable example.

Further, the protective film itself of the publication is required to be further improved. That is, according to the publication, the diameter of the protective film is 80 μm.
The number of fish eyes above is specified. 80 μm diameter
In the case of the fish eye having a large diameter as described above, it is often the case that undissolved materials and deteriorated materials are incorporated in the film as described in the publication.

However, even if an attempt is made to improve the protective film of the above publication, a fish eye having a smaller diameter, for example, a film having even a small fish eye of about 30 μm is produced, the cause of the small fish eye is still unclear. It is enough. Moreover, it is insufficient to elucidate even the relationship between the fish eyes having such a minute diameter and the formation of the air voids because they are minute.
That is, the measurement of the fish eye is based on the observation of the light transmitted through the film and does not necessarily directly determine the unevenness of the film surface, therefore, in the case of a large-diameter fish eye, the unevenness of the film surface and its Even if it is admitted that there is a tentative correlation with the shape, in the case of a small fish eye of about 30 μm, as a matter of fact, the fish eye only shows after the resin flow, and the direct relation with the unevenness of the film surface. Sometimes there is no. Therefore, it is difficult to determine whether or not such a minute fish eye correlates with the unevenness of the film surface and its shape. Of course, it is difficult to determine whether or not the above-mentioned line drawing pattern can be formed.

Further, it is difficult to change the above compatibility as a protect film made of polyethylene film depending on the film forming method and its forming conditions, and it is necessary to change it from the essential properties of polyethylene itself. That is, no matter how the molding method and molding conditions of polyethylene are changed, there is a limit to the improvement of the compatibility as a protect film. In particular, it is difficult to obtain a useful protective film by changing the film forming method and the forming conditions thereof. For example, simply filtering polyethylene with a filter before or during film formation often does not show any improvement. It should be noted that the fish eye having a large diameter of 80 μm or more has a certain effect of reducing the number thereof by a physical removing means such as filter filtration, and therefore 3
It is presumed that there is an essential difference from a fine fish eye of about 0 μm.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems. To provide a novel protective film, a method for producing the same, and a laminate using the same by establishing a method for producing polyethylene, which is particularly suitable as a protective film for a dry film resist or the like that requires a high degree of protective function. is there.

[0012]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies on a method for producing low-density polyethylene of high pressure method and a polyethylene film obtained therefrom to solve the above-mentioned problems, and as a result, high reaction pressure, reaction system Based on the finding that the coexistence of the radical polymerization inhibitor and the like in (3) is related to the solution of the above problems, the inventors have succeeded in significantly improving the suitability as a protect film on the flat surface of protected articles such as dry film resists.

That is, the first aspect of the present invention is to pressurize ethylene with an ultra-high pressure compressor, and then polymerize ethylene at a reaction temperature of 190 to 300 ° C. in the presence of a radical polymerization initiator. The present invention relates to a protect film, which is made of polyethylene obtained by allowing a radical polymerization inhibitor to coexist in the reaction system in a proportion such that the concentration at the outlet is 5 to 1000 ppm by weight.

According to a second aspect of the present invention, in the first aspect of the present invention,
The present invention relates to a protect film having a reaction pressure of 167 MPa or more when polymerizing ethylene.

The third aspect of the present invention is the first or second aspect of the present invention.
In regard to the protect film, the radical polymerization inhibitor is a phenol-based or quinone-based compound.

In a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, a stirring tank reactor is used when ethylene is polymerized, and an average residence time in the reactor is 5 to 30 seconds. The present invention relates to a protect film that uses the following condition.

The fifth aspect of the present invention is 0.3 to 30 (g / 10).
Min) MFR and 0.913-0.930 (g / cm
^As a film having a density of ³ ) and a thickness of 30 μm, the haze is 1 to 50 (%), and the major axis is 30 present in the film.
From the polyethylene film, the density of fish eyes of μm or more and less than 0.20 mm is 40 pieces / 10 cm ² or less, and the density of fish eyes of major axis 0.20 mm or more is 1.0 pieces / 1.0 m ² or less. The present invention relates to a protective film which is characterized by

A sixth aspect of the present invention relates to a laminate in which the protect film according to any one of the first to fifth aspects of the present invention is directly laminated on the surface of the article to be protected.

The seventh aspect of the present invention is to pressurize ethylene with an ultra-high pressure compressor, and then to react at a reaction temperature of 1 in the presence of a polymerization initiator.
When polymerizing ethylene at 90 ° C to 300 ° C, the concentration of ethylene at the outlet of the ultrahigh pressure compressor is 5 to 1
The present invention relates to a method for producing polyethylene for a protect film, which comprises allowing a radical polymerization inhibitor in a proportion of 000 ppm by weight to coexist in a reaction system.

An eighth aspect of the present invention is the same as the seventh aspect of the present invention.
The present invention relates to a method for producing polyethylene for a protect film, which polymerizes ethylene at a reaction pressure of 167 MPa or more.

The ninth aspect of the present invention is the seventh or eighth aspect of the present invention.
Relates to a method for producing polyethylene for a protect film, wherein the polymerization inhibitor is a phenol-based or quinone-based compound.

The tenth aspect of the present invention is the seventh to ninth aspects of the present invention.
In the invention described above, the present invention relates to a method for producing polyethylene for a protect film, which comprises using a stirred tank reactor and polymerizing ethylene under conditions such that the average residence time in the reactor is 5 to 30 seconds.

The eleventh aspect of the present invention is the seventh to first aspects of the present invention.
0, the polyethylene obtained has a MFR of 0.3 to 30 (g / 10 min) and a value of 0.9.
It has a density of 13 to 0.930 (g / cm ³ ), and 30 μ
As a m-thick film, haze is 1 to 50 (%), and the presence density of fish eyes having a major axis of 30 μm or more and less than 0.20 mm in the film is 40 pieces / 10 cm ² or less,
The existence density of fish eyes with a major axis of 0.20 mm or more is 1.
The present invention relates to a method for producing polyethylene for a protect film, which is characterized in that the number is 0 / 1.0 m ² or less.

The twelfth aspect of the present invention is a polyethylene obtained by pressurizing ethylene with an ultrahigh pressure compressor, and then polymerizing ethylene in the presence of a polymerization initiator at a reaction temperature of 190 ° C. to 300 ° C. and a reaction pressure of 167 MPa or more. Is formed into a film, and 0.
MFR of 3 to 30 (g / 10 minutes) and 0.913 to
A film having a density of 0.930 (g / cm ³ ) and a thickness of 30 μm, a haze of 1 to 50 (%), and a fish eye existence density of 30 μm or more and less than 0.20 mm present in the film of 40 pieces. / 10 cm ² or less, a major axis of 0.20 mm or more, a polyethylene film having a fish eye existence density of 1.0 / 1.0 m ² or less, and directly laminating this polyethylene film as a protective film on the surface of the article to be protected. The present invention relates to a method for producing a characteristic laminate.

The thirteenth aspect of the present invention is to pressurize ethylene with an ultra-high pressure compressor, and then polymerize ethylene at a reaction temperature of 190 ° C. to 300 ° C. in the presence of a polymerization initiator. Is 5 to
A polyethylene obtained by coexisting a radical polymerization inhibitor in an amount of 1000 ppm by weight in the reaction system was formed into a film to have an MFR of 0.3 to 30 (g / 10 minutes) and 0.913 to 0. A film having a density of 930 (g / cm ³ ) and a thickness of 30 μm and a haze of 1 to 50.
%, Major axis present in the film is 30 μm or more and 0.20 m
The presence density of fish eyes less than m is 40 pieces / 10 cm ²
Hereinafter, a polyethylene film having a major diameter of 0.20 mm or more and a fish eye existence density of 1.0 / m ² or less, and the polyethylene film is directly laminated on the surface of a protected article as a protect film. Manufacturing method.

In the fourteenth aspect of the present invention, ethylene is pressurized by an ultrahigh pressure compressor, and then ethylene is polymerized in the presence of a polymerization initiator at a reaction temperature of 190 ° C. to 300 ° C. and a reaction pressure of 167 MPa or more. A polyethylene obtained by allowing a radical polymerization inhibitor to coexist in the reaction system at a ratio such that the concentration at the outlet of the compressor with respect to ethylene is 5 to 1000 ppm by weight is formed into a film to give 0.3 to 30.
(G / 10 min) MFR and 0.913-0.930
As a film having a density of (g / cm ³ ), a thickness of 30 μm, a haze of 1 to 50%, a fish eye existence density of 30 μm or more and less than 0.20 mm of major axis present in the film of 40 pieces / 10 cm ² or less, A polyethylene film having a major diameter of 0.20 mm or more and a fish eye existing density of 1.0 / m ² or less, and the polyethylene film is directly laminated on the surface of a protected article as a protect film. Regarding the method.

The fifteenth aspect of the present invention relates to the contact-type protect film according to any one of the first to fifth aspects of the present invention, which is used by being directly laminated on the surface of the object to be protected.

[0028] A sixteenth aspect of the present invention is the protective film produced according to any of the seventh to eleventh aspects of the present invention,
The present invention relates to a method for producing a contact-type protect film, which is used by being directly laminated on the surface of an object to be protected.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. The polyethylene used in the protect film of the present invention is produced by a high pressure radical polymerization method of ethylene using an organic peroxide, oxygen or the like as a radical polymerization initiator.

In this high-pressure radical polymerization, generally, ethylene is pressurized by an ultrahigh-pressure compressor and then introduced into a tubular reactor or a stirred tank reactor to polymerize ethylene in the presence of a radical polymerization initiator, This is a method of producing polyethylene by depressurizing appropriately thereafter.

The radical polymerization initiator is a compound which generates a free radical, such as oxygen, t-butylperoxypivalate, t-butylperoxyoctoate, t-butylperoxyacetate, t-butylperoxybenzoate and the like. The organic peroxides of The radical polymerization initiator is injected into the reactor by a conventional method.

The pressurization of ethylene is usually achieved by two-stage compression of a high pressure compressor and an ultrahigh pressure compressor. About 1 ethylene
The high-pressure compressor boosts the pressure to 0 to 40 MPa, and the ultra-high-pressure compressor boosts the reaction pressure from there.
The ethylene from the ultra-high pressure compressor is introduced into the reactor where it polymerizes. As the reactor, either the tubular reactor or the stirred tank reactor described above can be adopted. A stirred tank reactor is preferred.

The reaction temperature for ethylene polymerization is 190 to 30.
The temperature is 0 ° C, preferably 200 to 280 ° C, more preferably 210 to 265 ° C. When the reaction temperature is out of the above range, the cross-linking reaction between the polymers is promoted and the existing density of fish eyes is increased. Here, the lower limit of the reaction temperature of the polymerization represents the temperature of the part where the polymerization proceeds and the temperature rises relatively clearly downstream of the site where the ethylene gas and the polymerization initiator first contact in the reactor, The upper limit represents the maximum temperature in the reactor.

Incidentally, polar monomers of appropriate types and amounts such as vinyl acetate and (meth) acrylic acid ester can be copolymerized with ethylene as long as the performance as a protect film is not impaired.

In the polymerization of ethylene of the present invention, it is important to carry out the polymerization at a certain reaction pressure or higher. Here, the reaction pressure means the lowest pressure in the reactor, and is specifically 167 MPa or more, preferably 190 MPa or more. When the reaction pressure is lower than 167 MPa, a region where phase separation of ethylene and the polyethylene-rich phase occurs occurs in the reactor, and the polyethylene-rich phase formed thereby increases the probability of contact between polyethylenes, resulting in a polyethylene crosslinking reaction. Is more likely to occur. Therefore, 1
When the pressure is less than 67 MPa, it is difficult to reduce the fine fisheye. If the reaction pressure is 167 MPa or more, the phase in the reactor is uniform, and thus the crosslinking reaction is hard to occur. The higher the polymerization pressure, the better, but
Since the pressure resistance of each device in the process is limited, the upper limit of the reaction pressure is substantially about 393 MPa.

The average residence time in the reactor during polymerization is 5
~ 30 seconds, preferably 8-25 seconds, more preferably 1
The supply rate of the reaction raw material and the like are controlled so as to be 0 to 18 seconds. If the average residence time is shorter than 5 seconds, the unreacted radical polymerization initiator will flow out to the downstream of the reactor, and the reaction will be started in the pipe or the separator where the stirring state is bad. If the initiator decomposes in a poorly dispersed state, the polymer may locally crosslink to form fish eyes and may lead to an abnormal reaction. If it is longer than 30 seconds, the produced polymer is exposed to the environment in which free radicals are present for a long time, so that the crosslinking is accelerated. Here, the average residence time in the reactor means a value obtained by dividing the reactor internal volume (m ³ ) by the volumetric flow rate of all ethylene gas entering the reactor (m ³ / sec).

In the ethylene polymerization of the present invention, in addition to the above-mentioned reaction pressure of 167 MPa or more, it is preferable to further coexist a polymerization inhibitor in the reaction system. By using these two means in combination, it is possible to synergistically achieve reduction of fish eyes, particularly fine fish eyes.
The amount of the polymerization inhibitor added to the reaction system is 5 to 1000 ppm by weight based on ethylene. Preferably 50-50
0 weight ppm, more preferably 100 to 300 weight p
pm. Of course, the amount of the polymerization inhibitor is an amount that does not inhibit the polymerization of the monomer itself such as ethylene. Although it varies somewhat depending on the degree of the polymerization inhibitory effect of the polymerization inhibitor used, if it is less than the lower limit, the fisheye reducing effect is insufficient, and if it exceeds the upper limit, the fisheye reducing effect is capped and the consumption of the polymerization initiator increases sharply. It is not practical because it invites. Since unreacted ethylene is usually circulated and reused as will be described later, the flow rate becomes maximum at the outlet of the ultra-high pressure compressor. The polymerization inhibitor is allowed to coexist in the reaction system at such a ratio that the concentration becomes the above concentration at the outlet.

The polymerization inhibitor can be injected / added to any desired location as long as it coexists in the reaction system. However, when adding at a location after the outlet of the ultra-high pressure compressor, an ultra-high pressure pump for adding the polymerization inhibitor is required. Therefore, the injection / addition position is preferably added before the outlet of the ultra-high pressure compressor. Specifically, it is before the inlet of the high-pressure compressor or downstream of the outlet of the high-pressure compressor and upstream of the inlet of the ultra-high pressure compressor. Further, the polymerization inhibitor may be added alone, or may be added in advance to the reaction system after being mixed with ethylene, a molecular weight modifier and the like in advance.

As the polymerization inhibitor to be coexisted in the reactor, any radical polymerization inhibitor of ethylene can be used. Specific examples include phenol compounds and quinone compounds. Specifically, hydroquinone, monomethyl ether hydroquinone, 2,
6-di-t-butyl-4-methylphenol, 2,6-di-t-butyl-4-ethylphenol, 3,5-bis (1,1-dimethylethyl) -4-hydroxybenzenepropionic acid octadecyl ester, thio Examples thereof include bisphenol, quinone, 4-t-butylpyrocatechol and the like. Among these, monomethyl ether hydroquinone, 2,6-di-t-butyl-4-methylphenol, 2,6-di-t-butyl-4-, which has a relatively low molecular weight, is not too polar, and has good dispersibility in ethylene. Ethylphenol and the like are preferred. Among these, 2,6-di-t-butyl-4-methylphenol and 2,6-di-t-butyl-4-ethylphenol which do not excessively suppress the polymerization reaction are more preferable. These polymerization inhibitors may be used alone or in 2
You may use it in combination of 2 or more types. Further, the polymerization inhibitor can be added to the reaction system as a solution dissolved in a solvent. The solvent used here has, for example, 6 to 14 carbon atoms.
Included are some saturated hydrocarbons. Depending on the case, you may use these solvents in combination of 2 or more types. It is desirable that this solvent is a good solvent for the polymerization inhibitor and does not adversely affect the polymerization system. Further, in consideration of the boiling point and the efficiency of separation from the polymer, it is preferable to select the one in which the amount remaining in the polymer is as small as possible.

In the polymerization, a molecular weight modifier may be appropriately used, and various chain transfer agents can be used. Specific examples of chain transfer agents include olefin compounds such as propylene, butene and hexene, paraffins such as ethane, propane and butane, and aromatic hydrocarbons such as toluene, xylene and ethylbenzene.

After the polymerization, if the pressure is appropriately released, the desired polyethylene such as MFR (JIS K 6760) can be obtained.
(Temperature 190 ° C., load 2.16 kg)) is 0.3 to 30
(G / 10 minutes), density (JIS K 6760) is 0.
913 to 0.930 (g / cm ³ ) of polyethylene is obtained. The unreacted ethylene recovered during depressurization can be circulated and reused by appropriately increasing the pressure again. The MFR of the obtained polyethylene may be 0.3 to 30, and 1 to 1
0 is preferable and 2-5 is especially preferable. If the MFR is outside this range, stable film formation becomes difficult.
The density may be 0.913 to 0.930, and 0.9
18 to 0.930 is preferable, and 0.920 to 0.928
Is particularly preferable. If the density is less than 0.913, the rigidity of the film is lowered, and workability may be deteriorated too much.
When it exceeds 0.930, the flexibility of the film is lowered, and when it is used as a protective film, the adhesion of the film may be problematic.

As a film forming method for the protect film, a known film forming method can be adopted. For example, in forming the film, any film forming method such as an inflation method (air cooling method, water cooling method) or a T-die method can be used, and in some cases, a stretching treatment such as a uniaxial stretching treatment or a biaxial stretching treatment can be added. . The molding temperature and the take-up speed in film forming are not particularly limited, but generally, the molding temperature of 130 to 230 ° C. and the take-up speed of 5 to 40 m / min are suitable. Although the film thickness is appropriately selected, the thickness of the protect film is preferably about 10 to 100 μm, and more preferably 5 to 30 μm. In addition, the polyethylene constituting the protect film of the present invention includes linear low-density polyethylene, high-density polyethylene, within a range that does not adversely affect the specifications of the fisheye of the present invention,
A polyolefin resin such as an ethylene-propylene copolymer or an ethylene-butene copolymer may be blended.
If necessary, additives usually used for polyolefins, specifically, antioxidants, antiblocking agents, lubricants, antistatic agents, ultraviolet absorbers and the like may be added.

When a radical polymerization inhibitor coexists in the polymerization reaction system to produce polyethylene, a certain amount of the radical polymerization inhibitor present in the reaction system remains in the product. When the residual radical polymerization inhibitor also has an antioxidant ability and the concentration thereof is sufficient, it is possible to add no antioxidant to the product polyethylene.

The protect film of the present invention obtained by molding polyethylene as described above is 3
When measured with a 0 μm thick film, haze (JIS
(Measured by K7105) is 1 to 50 (%), the presence density of fish eyes having a major axis of 30 μm or more and less than 0.20 mm in the film is 40 pieces / 10 cm ² or less, and a major axis of 0.20.
The existence density of fish eyes of 1.0 mm or more is 1.0 / 1.0
It satisfies m ² or less.

Here, the fish eye means an optically non-uniform region observed from the light transmitted through the film. Large-sized fish eyes, for example, those having a diameter of about 80 μm are often foreign substances. However, a fish eye having a minute diameter, for example, a fish eye having a diameter of about 30 μm may not be sufficiently elucidated due to its minute diameter, and the cause thereof is unknown and its solution is insufficient. Furthermore, it cannot be expected that the small-diameter fish eyes as an optically non-uniform region observed in transmitted light will directly correlate with the occurrence of air voids.

Fish-eyes having a major axis of 0.20 mm or more (large fish-eyes) are mainly caused by oxidative deterioration resin and the like. Since they have a significant influence on the film smoothness, it is preferable that they are not present as much as possible.
0 pieces / 1.0 m ² or less, preferably 0.5 pieces / 1.0 m
² or less, more preferably 0.3 / 1.0 m ² or less. Further, the upper limit of the major axis of the large fish eye should be limited to about 1.5 mm from the viewpoint of preventing serious appearance defects and poor adhesion.

On the other hand, as for the fish eyes having a major axis of less than 0.20 mm, the number of fish eyes having a major axis of 30 μm or more and less than 0.20 mm (small fish eyes) is 40/10 cm.
² or less, preferably 10 pieces / 10 cm ² or less, and more preferably 2 pieces / 10 cm ² or less. The lower limit of the number of small fish eyes is usually 0.05 small fish eyes / 10 cm ² from the viewpoint of production condition management of the film. The number range of the small fish eyes is 80
The number of fish eyes of μm or more is approximately equal to or less than 5 / m ² . It was observed that the number of fish eyes increased progressively as the diameter decreased, so even if the number of fish eyes of 80 μm is 0 (zero), fish eyes of about 30 μm have a considerable amount. Usually there are a number (30
Even if it is difficult to measure the microscopic fisheye of μm, the measurement method is difficult).

The density of fish eyes in the film of the present invention is determined by a simple clean room (cleanliness: F
ederal standard 209D class 1
0000), an air-cooled blown film forming machine (Modern Machinery, extruder barrel diameter 45 mm,
Using a die diameter of 80 mm, set the temperature of the extruder to 130 to 150 ° C for the cylinder section, 150 ° C for the adapter / die section,
It is obtained from a film having a thickness of 30 μm formed under the conditions of a take-up speed of 20 m / min and a blow-up ratio of 2.0.

The fisheye measuring method is as follows.

The large fish eyes having a major axis of 0.20 mm or more are measured by in-line measurement with a laser counter or a CCD camera attached to a film molding machine, and the small fish eyes having a major axis of 30 μm or more and less than 0.20 mm have a resolution of 1600 dpi. The method is based on the method of off-line analysis of an image in the transmission mode using the CCD scanner of. The measurement area is 30 μm or longer and 0.20
In the case of measuring a small fish eye of less than mm, it is set to 30 cm ² or more, and in the case of measuring a large fish eye of 0.20 mm or more in major axis, it is set to 100 m ² or more.

Next, the use of the protect film of the present invention will be exemplified. As described above, the dry film resist is formed by forming the resist layer of the photosensitive resin layer on the base film made of polyethylene terephthalate or the like,
Further, a polyethylene film as a protect film which is in direct contact with the resist layer is laminated on the upper surface thereof. Any conventionally known resist can be used as long as it can be used as a dry film resist. A thinner film resist layer is preferable because the resolution is improved. Particularly, from the viewpoint of resolution, a thinner resist layer is required in recent years. The protective film of the present invention is particularly suitable for 3
It can be suitably used by laminating on a resist layer having a thickness of 0 μm or less, preferably 25 μm or less. The lower limit of the thickness is not particularly limited, but is usually 0.1 μm or more, preferably 1 μm or more.

A method of laminating a polyethylene film after forming a resist film on the base film can be a conventionally known method.

An outline of the resist process using the laminate of the film resist thus obtained and the polyethylene film, specifically, the laminate of the constitution of protect film / film resist / base film will be described below.

That is, first, any conventionally known film resist can be adopted as the film resist. For example, the above-mentioned Japanese Patent Laid-Open No. 11-1538.
(A) a binder polymer obtained by copolymerizing acrylic acid or methacrylic acid and an alkyl ester thereof as a constituent monomer, as exemplified in JP-A-61-
The film resist may be a photosensitive composition containing (b) a monomer having at least one photopolymerizable ethylenically unsaturated group in the molecule and (c) a photopolymerization initiator. As these, commercially available products can be appropriately used.

Also, a base film (supporting film)
Can be a polyester film, for example, a film made of polyethylene terephthalate. The thickness is not particularly limited, but is usually selected from the range of 1 to 30 μm. As the base film, a commercially available product can be appropriately used.

The laminate having the above-mentioned protect film / film resist / base film was peeled off from the protect film to form a resist layer on one surface of the metal substrate, with the base film being the uppermost layer. Affix. That is, the protective film is attached so that the resist surface peeled off is in contact with the metal substrate surface. The surface of the metal substrate is appropriately polished in advance. A pressure-bonding roll can be appropriately used for attachment. In addition,
The peeled protective film can be discarded or recycled as appropriate for use. Polyethylene obtained by the high-pressure radical polymerization method adheres to the resist surface, but the adhesiveness to the resist is not so high that the releasability is good.
Therefore, the resist rarely remains on the protect film during peeling.

Then, the film resist is irradiated with ultraviolet rays and active rays other than the above through a photomask having a desired pattern, and a part of the resist layer is photocured or photolyzed in accordance with the pattern, and the remaining resist. Leave the layers unchanged. After that, a developing solution such as an organic solvent or an alkaline aqueous solution is used to dissolve and remove the resist layer in the uncured portion of the positive resist, while leaving the portion of the photocured resist layer. Thus, a cured resist layer having a desired pattern can be formed on the substrate. After that, a circuit or the like is formed on the metal substrate by etching if necessary.

The protect film of the present invention has no physical or chemical influence on the film resist surface which is in direct contact with the film, the occurrence of air voids is small, and as a result, pattern defects occur during pattern formation. Less likely to produce a cured resist layer. Therefore, it is suitable as a protect film that is in direct contact with the resist film. Further, as disclosed in the above publication, the thinner the resist thickness is, the more easily defects such as pattern defects are generated.
m or less, 0.1 μm or more, preferably 1 to 25 μm, even when used by being laminated on a thin dry film resist, the occurrence of the air voids is small, and as a result, a cured resist layer having a pattern defect during pattern formation. Rarely occurs. The protect film of the present invention is used for protection of an appropriate article requiring similar protection other than the dry film resist.

[0059]

EXAMPLES The present invention will be described below with reference to specific examples.

Example 1 Using a high-pressure low-density polyethylene production facility having a stirred tank reactor, in the presence of a radical polymerization initiator, the reaction temperature was from 210 ° C. to 265 ° C. at the lowest temperature, and the reaction pressure was 196 MPa.
The average residence time in the reactor was 17 seconds, 2,6-di-t-from a site downstream of the high pressure compressor outlet and upstream of the ultra high pressure compressor inlet.
Under the condition that an isoparaffin solution of butyl-4-methylphenol (concentration 150 g / l) was injected and the concentration of 2,6-di-t-butyl-4-methylphenol in ethylene at the outlet of the ultrahigh pressure compressor was 170 ppm by weight. , Manufactured polyethylene.

Prior to the production of the target product, a similar product having substantially the same MFR and density was produced for 8 hours or more, and sufficient replacement in the process system was carried out. In addition, as for process points that pass between resin pelletization and bagging, perform thorough cleaning to prevent residual polyethylene with different molecular weights from entering and to prevent dust contamination in the air during bagging as much as possible. Consideration for dust prevention was made.

As a result, a lot of about 40T was produced as a product. Since the homogenization operation is performed by dry blending within the lot, the physical properties and quality are constant.

Cleanliness class 10000, paying attention to prevention of dust contamination in the handling process and prior cleaning of accumulated matters in the molding machine.
(Federal Standard 209D) in a simple clean room, air-cooled inflation film molding machine (Modern Machinery, extruder barrel diameter 4)
5mm, full flight screw, wearing filter 12
0 mesh, die diameter 80 mm), the temperature of the extruder is set to 130 to 150 ° C., the adapter / die portion is 150 ° C., the take-up speed is 20 m / min, the blow-up ratio is 2.0, and the thickness is 30 μm. Was formed into a film.

The existence density of large fish eyes having a major axis of 0.20 mm or more is determined by in-line laser fish eye counter (Laser Eye;
The number was measured with a PLS-J04T type) and converted per a predetermined unit area. An area of 320 m ^{2 was} measured once, and this measurement was performed three times for each product lot to calculate the average value.

The existence density of small fish eyes having a major axis of 30 μm or more and less than 0.20 mm was determined by cutting the obtained film into about A4 size and using a CCD scanner (EPSON E
S-2000) is used to set the resolution of any part to 1600d
Scanning was performed in the transmission mode of pi, and the obtained image was analyzed and converted into a predetermined area for determination. 33.3 per measurement
The measurement was performed for an area of cm ² , and the film sample was changed, and a total of 3 measurements were performed, and the average value was calculated. Table 1 shows the measurement results of the fish eye abundance.

When this product was applied to a dry film resist protect film, it was possible to sufficiently cope with a drawing pattern having a minimum line width of 20 μm.

The formation of the drawing pattern and its determination were carried out as follows (the following Examples and Comparative Examples were also carried out according to this method).

That is, the above polyethylene film (thickness 30 μm) was laminated as a protect film on the resist of 16 μm polyethylene terephthalate film (supporting film) / commercial film resist (20 μm).

The protective film was peeled off from the laminated film having the three-layer structure and laminated on a copper-clad laminated plate. Then, exposure, development and etching were carried out by a conventional method with a line drawing pattern mask having a minimum line width of 20 μm to form a line drawing on the copper plate. By observing the formed line drawing with a microscope, the compatibility with the drawing pattern by the line drawing was determined.

Example 2 A raw material polyethylene was produced (about 80 T) under the same conditions and method as in Example 1, except that the isoparaffin solution of 2,6-di-t-butyl-4-methylphenol was not injected into the system.
Film formation and measurement were performed. Table 1 shows the measurement results of the fish eye abundance.

When this product was applied to a protective film of a dry film resist, it was possible to sufficiently cope with a drawing pattern by a line drawing having a minimum line width of 30 μm. However, some defects were recognized at the minimum line width of 20 μm.

Example 3 An isoparaffin solution of 2,6-di-t-butyl-4-methylphenol was not injected into the system, and the reaction pressure was 173MP.
A raw material polyethylene was produced (about 80 T) under the same conditions and methods as in Example 1 except that a was used, and a film was formed and measured. Table 1 shows the measurement results of the fish eye abundance.

When this was applied to a protective film of a dry film resist, it was possible to cope with a drawing pattern with a line drawing having a minimum line width of 75 μm. Further, it can be preferably used for general-purpose protect film applications for acrylic plates and the like (hereinafter the same).

Example 4 Using a high-pressure process low-density polyethylene production facility having a tubular reactor, in the presence of a radical polymerization initiator, the reaction temperature was at least 1 part.
At 95 ° C to 275 ° C at the highest temperature and at a reaction pressure of 240 MPa, the same measures as in Example 1 were carried out to produce polyethylene (about 50T), and the film was formed under the same conditions and methods as in Example 1.
The measurement was performed. Table 1 shows the measurement results of the fish eye abundance.

When this was applied to a protective film of a dry film resist, it was possible to cope with a drawing pattern with a line drawing having a minimum line width of 75 μm. Further, it could be suitably used for general-purpose protect film applications.

Comparative Example 1 Polyethylene production (about 40 T), film molding, and fisheye measurement were carried out according to Example 3 except that the reaction pressure was 150 MPa. Table 1 shows the measurement results of the fish eye abundance.

When this was applied to a dry film resist protect film, the minimum line width was 100 μm.
Some problems occurred even in the above low-grade applications.

Comparative Example 2 Polyethylene production (about 40 T) was carried out in accordance with Example 3 except that the reaction temperature was 175 ° C. at the lowest temperature and 305 ° C. at the highest temperature.
Film molding and fisheye measurement were performed. Table 1 shows the measurement results of the fish eye abundance.

When this was applied to a dry film resist protect film, the minimum line width was 100 μm.
Some problems occurred even in the above low-grade applications.

Comparative Example 3 Example 3 was repeated except that the average residence time in the reactor was 34 seconds.
Polyethylene production (about 30 T), film molding, and fish eye measurement were carried out according to. Table 1 shows the measurement results of the fish eye abundance.

When this product was applied to a dry film resist protect film, the minimum line width was 100 μm.
The above drawing patterns could be used. Also,
It was suitable for use in general-purpose protect films.

[0082]

[Table 1]

[0083]

The presence and the number of minute fish eyes having a size of 30 μm or less are difficult to change depending on the film forming method and the forming conditions thereof, and it is necessary to change from the essential properties of polyethylene itself. This is because the cause of generation of fine fish eyes of 30 μm or less has not been clarified yet.

In the present invention, by adopting a polymerization method in which ethylene is polymerized under a high pressure which enables polymerization in a homogeneous phase, and at the same time, a polymerization inhibitor is allowed to coexist, a thin resist layer thickness is obtained. Even if it is, it is possible to provide an effective protective film made of an excellent polyethylene film.

As a result, by using the protect film of the present invention, even a drawing pattern having a minimum line width of 20 μm can be sufficiently dealt with.

Low-density polyethylene produced by the high-pressure radical polymerization method is flexible and therefore has good adhesion to the film resist surface, and is therefore convenient for exhibiting a protective function. Since the peelability from the film resist is good, the work of laminating on the metal substrate can be easily performed. Therefore, the polyethylene film of the present invention is suitable as a protect film.

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Claims (16)

[Claims] 1. The pressure of ethylene is boosted by an ultra-high pressure compressor,
Then, in the presence of a radical polymerization initiator, the reaction temperature is 190 ° C.
When polymerizing ethylene at ˜300 ° C., the concentration of ethylene at the outlet of the ultra high pressure compressor is 5˜1000.
A protective film comprising polyethylene obtained by allowing a radical polymerization inhibitor in a proportion of ppm by weight to coexist in a reaction system. 2. The reaction pressure for polymerizing ethylene is 1
The protect film according to claim 1, which has a pressure of 67 MPa or more. 3. The protect film according to claim 1, wherein the radical polymerization inhibitor is a phenol-based or quinone-based compound. 4. The protective film according to claim 1, wherein a stirring tank reactor is used when ethylene is polymerized, and conditions under which the average residence time in the reactor is 5 to 30 seconds are used. 5. A 30 μm thick film having an MFR of 0.3 to 30 (g / 10 minutes) and a density of 0.913 to 0.930 (g / cm ³ ) and a haze of 1 to 50.
(%), Major axis present in the film 30 μm or more 0.2
Presence of fisheye of less than 0 mm is 40 pieces / 10c
m ² or less, the protective film characterized by comprising a polyethylene film, wherein the fish-eye the density of more than the major diameter 0.20mm is 1.0 or /1.0M ² below. 6. A laminate in which the protect film according to claim 1 is directly laminated on the surface of a protected component (excluding the surface of a film resist). 7. The pressure of ethylene is boosted by an ultra-high pressure compressor,
Then, in the presence of a polymerization initiator, the reaction temperature is 190 ° C to 300 ° C.
When polymerizing ethylene at ℃, the concentration of ethylene at the outlet of the ultra-high pressure compressor is 5 to 1000 weight pp.
A method for producing a protect film, which comprises forming a polyethylene film obtained by allowing a radical polymerization inhibitor in a proportion of m to coexist in a reaction system. 8. The method for producing a protect film according to claim 7, wherein ethylene is polymerized at a reaction pressure of 167 MPa or more. 9. The method for producing a protect film according to claim 7, wherein the polymerization inhibitor is a phenol type or quinone type compound. 10. The process for producing a protective film according to claim 7, wherein ethylene is polymerized using a stirred tank reactor under conditions such that the average residence time in the reactor is 5 to 30 seconds. Method. 11. The polyethylene obtained is 0.3 to 3
0 (g / 10 min) MFR and 0.913-0.93
As a film having a density of 0 (g / cm ³ ) and a thickness of 30 μm, haze is 1 to 50 (%), and the presence density of fish eyes having a major axis of 30 μm or more and less than 0.20 mm in the film is 40 pieces / 10 cm. ² or less, major axis 0.20 m
The presence density of fish eyes of m or more is 1.0 / 1.0 m
^{It is 2} or less, The manufacturing method of the protect film of any one of Claim 7 to 10 characterized by the above-mentioned. 12. The pressure of ethylene is increased by an ultra-high pressure compressor, and then the reaction temperature is 190 ° C. to 3 in the presence of a polymerization initiator.
Polymerize ethylene at 00 ° C. and a reaction pressure of 167 MPa or more, form a film of the obtained polyethylene, and form 0.3 to 30.
(G / 10 min) MFR and 0.913-0.930
As a film having a density of (g / cm ³ ), a thickness of 30 μm, a haze of 1 to 50 (%), and a density of fish eyes having a major axis of 30 μm or more and less than 0.20 mm present in the film of 40 pieces / 10 cm ² Below, major axis 0.20 mm
The above fish eye density is 1.0 / 1.0 m ²
A method for producing a laminate, comprising the following polyethylene film, which is directly laminated on the surface of a protected article (excluding the surface of the film resist) as a protective film. 13. The pressure of ethylene is increased by an ultra-high pressure compressor, and then the reaction temperature is 190 ° C. to 3 in the presence of a polymerization initiator.
When polymerizing ethylene at 00 ° C., a polyethylene film obtained by coexisting in the reaction system a radical polymerization inhibitor in a ratio such that the concentration of ethylene at the outlet of the ultrahigh pressure compressor is 5 to 1000 ppm by weight is formed. hand,
MFR of 0.3-30 (g / 10 min) and 0.913
As a film having a density of ˜0.930 (g / cm ³ ), a thickness of 30 μm, a haze of 1 to 50%, and a density of fish eyes having a major axis of 30 μm or more and less than 0.20 mm in the film of 40 / 10 cm ² or less, major axis 0.
Presence of fish eyes of 20 mm or more is 1.0 / m
^A method for producing a laminate, which comprises forming a polyethylene film of ² or less, and directly laminating this polyethylene film as a protect film on the surface of the protected material (excluding the surface of the film resist). 14. The pressure of ethylene is increased by an ultrahigh pressure compressor, and then the reaction temperature is 190 ° C. to 3 in the presence of a polymerization initiator.
It was obtained by polymerizing ethylene at 00 ° C. and a reaction pressure of 167 MPa or more by coexisting in the reaction system a radical polymerization inhibitor in a ratio such that the concentration at the outlet of the ultrahigh pressure compressor was 5 to 1000 ppm by weight with respect to ethylene. Polyethylene film is formed to 0.3 to 30 (g / 10
Min) MFR and 0.913-0.930 (g / cm
^As a film having a density of ³ ) and a thickness of 30 μm, haze is 1 to 50%, and a major axis present in the film is 30 μm.
The fish-eye existence density of less than 0.20 mm is 40
A polyethylene film having a number of particles / 10 cm ² or less and a major axis of 0.20 mm or more and a fish eye existence density of 1.0 / m ² or less, and the polyethylene film is used as a protective film on the surface of the article to be protected (however, the surface of the film resist is Except for the above), the method for producing a laminated body is characterized by directly laminating. 15. The protect film according to any one of claims 1 to 5, wherein the protect film is a contact-type protect film used by being directly laminated on the surface of the object to be protected. 16. The protective film produced according to claim 7, which is a contact-type protective film used by being directly laminated on the surface of an object to be protected.
The method for producing a protective film according to.