JPS6061259A - Polyester film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyester film with improved surface properties, particularly slipperiness, by providing a coating layer.

Biaxially oriented polyester film, especially biaxially oriented polyethylene terephthalate film, has good transparency, dimensional stability,
Mechanical properties, electrical properties.

Excellent gas barrier properties, heat resistance, chemical resistance, etc.

It is used as a base material for packaging materials, electrical insulating materials, photosensitive materials using scissor salts, diazo compounds, photosensitive resins, etc., drafting materials, electrophotographic materials, magnetic recording materials, etc.

As the storage of magnetic recording media becomes more precise and the capacitance of capacitors increases, polyester films that are used are increasingly required to be flat and have good slip properties. The key components are for optics,
The same goes for taking pictures of m children.

Conventionally, methods for improving the slipperiness of polyester films include adding Kd organic or inorganic particles to polyester (additive particle method), and precipitating transesterification catalyst residues during the weighting of polyester. Method(
(extracted particle method).

A method using a polymer blend A method using a polyester composition, such as a method of blending a lubricant for 1M yarn, is used. However, with methods such as the additive particle method, precipitated particle method, and polymer blending, if one of slipperiness and flatness is the same, the other decreases, and it is difficult to achieve both of them, and optical There are also problems with the application, such as the need to satisfy transparency. Although the method of blending lubricants can achieve smoothness up to a certain level, there are problems such as contamination of the process or product due to lubricant transfer, difficulty in achieving and maintaining a high degree of vacuum during vapor deposition, and difficulty in forming a laminate. There are many problems such as decreased adhesion between layers.

In contrast to conventional methods using compositions, recently there have been reports in which films are coated with missing layers and have mountain-like protrusions on the surface.
- It has been proposed in publications such as 舊2g24.

The present inventors previously discovered that a biaxially oriented polyester film having a coating layer composed of an acrylic resin and a polyester resin has excellent surface properties (Japanese Patent Application Laid-Open No.
g-12 Hirotsusi issue/publication). Concerning the slipperiness of a film with a coating layer.

As a result of further investigation, we found that films with coating layers mainly composed of poly, ester resin, polyurethane resin, or butadiene-based elastomer resin had poor slipperiness, whereas acrylic resin was used as a component of the coating layer. The films generally had good slip properties. It is assumed that the polarity of the resin is related to its flexibility, and that films with coating layers made of acrylic resin, polyester resin, and protrusion-forming resin, and coating layers made of these and silica sol have excellent properties. It has been found that there are improved surface properties, especially improved slip properties. Furthermore, as a result of examining the coating layer mainly composed of acrylic resin, we found that when silica sol was blended into the coating layer consisting of acrylic resin and polyester resin without using protrusion-forming resin, surprisingly, a significant It was discovered that the film has slipperiness even though it does not have protrusions, and the present invention was achieved.

That is, the present invention relates to a polyester film or a biaxially stretched polyester film provided with a coating layer consisting of a water-soluble polyester resin and silica sol.

The polyester film constituting the substrate in the present invention is a polyethylene terephthalate film in which gO mole or more of its constituent units are ethylene terephthalate. Examples of copolymerization components other than the ethylene terephthalate component include diethylene glycol and propylene glycol.

Diol components such as neopentyl glycol, polyethylene glycol, polytetramethylene glycol, /, 4'-cyclohexane dimetatool, isophthalic acid, t-naphthalene dicarboxylic acid, terthodiosulfoisophthalic acid, adipic acid, azelaic acid, dicarboxylic acid components such as sebacic acid and its ester-forming derivatives;
Oxymonocarboxylic acids such as oxybenzoic acid and its ester-forming derivatives can be used.

In the composition of the polyester film constituting the substrate in the present invention, additive particles, precipitated particles, other catalyst residues that form protrusions on the film surface, and resins other than polyethylene terephthalate are used for high-density magnetic recording using vapor-deposited metal as a magnetic layer. Although it is preferable to reduce the amount as much as possible for material applications, it may be contained in amounts conventionally used by those skilled in the art, depending on the application. That is, the film of the present invention has
Polyester film is designed to give slippery properties to films that have surface protrusions, which could not be put to practical use in the past. The protrusion-forming agent may be included as appropriate depending on the purpose. As additives other than the protrusion-forming agent, antistatic agents, stabilizers, lubricants, crosslinking agents, etc. can be used as necessary.

The water-dispersible or water-soluble acrylic resin (hereinafter abbreviated as "1 acrylic resin") used in the present invention preferably has an alkyl acrylate or alkyl methacrylate as a main component, and the main component is 30 to 90 mol. It is a water-soluble or water-dispersible resin containing from 10 to 10 moles of a vinyl monomer component that can be copolymerized with these and has a functional group. The vinyl monomer possesses the property of imparting hydrophilicity to the resin and improving the water dispersibility of the resin,
Alternatively, it is preferable to have a functional group that improves the adhesion between the resin and the polyester film or other coating layer provided on the undercoat layer, or has a good affinity with the polyester resin blended as a coating agent. Preferred functional groups include carboxyl groups or salts thereof, acid anhydride groups,
These include a sulfonic acid group or a salt thereof, an amide group or an alkylolated amide group, an amine group (including substituted amino groups), a striped alkylolated amino group or a salt thereof, a hydroxyl group, an epoxy group, and the like. Particularly preferred are carboxyl groups or salts thereof, acid anhydride groups, epoxy groups, and the like. Two or more types of these groups may be contained in the resin.

The reason why it is preferable that the amount of alkyl acrylate or alkyl methacrylate in the acrylic resin is 30 moles or more is because coating formability, strength of the coating film, and blocking resistance are improved. It is preferable that the amount of alkyl acrylate or alkyl methacrylate in the acrylic resin is 90 moles or less because it can be introduced into a compound-deficient acrylic resin having a specific functional group as a copolymerization component to make it water-solubilized and water-soluble. This is to facilitate dispersion and to stabilize its state over a long period of time.It also improves the adhesion between the coating layer and the polyester film layer, and improves the strength, water resistance, and chemical resistance of the coating layer through reactions within the coating layer. This is because it is possible to improve the adhesion between the film of the present invention and other materials.

Examples of alkyl groups in alkyl acrylates and alkyl methacrylates are methyl groups.

Ethyl, M-I+-propyl group, isopropyl group, n-
Butyl group, isobutyl group, t-butyl group.

-monoethylhexyl group, lauryl group, stearyl group, cyclohexyl group, etc.

) Vinyl monomers that have functional groups that copolymerize with alkyl acrylates or alkyl methacrylates are used.The following compounds that have functional groups such as 1-reactive functional groups, self-crosslinking functional groups, and hydrophilic groups are used. can.

Examples of compounds having a carboxyl group or a salt thereof, or an acid anhydride group include acrylic acid.

Examples include methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, metal salts of these carboxylic acids with sodium, ammonium salts, and maleic anhydride.

Examples of compounds having a sulfonic acid group or a salt thereof include vinyl sulfonic acid, styrene sulfonic acid, metal salts of these sulfonic acids with sodium, and ammonium salts.

Examples of compounds having an amide group or an alkylolated amide group include acrylamide.

Methacrylamide, N-methylmethacrylamide, methylolated acrylamide, methylolated methacrylamide, ureido vinyl ether.

Examples include β-ureido isobutyl vinyl ether and ureido ethyl acrylate.

Examples of compounds having an amino group or an alkylolated agno group or a salt thereof include diethylaminoethyl vinyl ether-co-aminoethyl vinyl ether, 3-aminobutyl vinyl ether + 2-aminobutyl vinyl ether, dimethylaminoethyl methacrylate, dimethyl Examples include aminoethyl vinyl ether, those obtained by methylolizing the amine group of solera, alkyl halides; those obtained by converting the amine group into Z-class compounds using dimethyl sulfate, sultone, etc.

Examples of compounds having a hydroxyl group include β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate,
β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, β-hydroxy vinyl ether, iohydroxypentyl vinyl ether, 6-hydroxyhexyl vinyl ether, polyethylene glycol monoacrylate, polyethylene glycol monomethacrylate, polypropylene glycol monoacrylate, polypropylene glycol monomethacrylate, etc. can give.

Examples of compounds having an epoxy group include glycidyl acrylate and glycidyl methacrylate.

Furthermore, in addition to the above, the following compounds may be used in combination: acrylonitrile, methacrylate, styrenes, phthyl vinyl ether, maleic acid mono- or dialkyl esters, fumaric acid mono- or dialkyl esters, itaconic acid mono- or dialkyl esters. Alternatively, dialkyl esters, methyl vinyl ketone, vinyl chloride, vinylidene chloride, vinyl acetate, vinyl pyridine, vinyl pyrrolidone, vinyl trimethoxysilane and the like may be mentioned, but are not limited to these.

The acrylic resin may contain a surfactant.

However, when the acrylic fIM resin has a large amount of opening compared to the polyester resin.

Low-molecular-weight surfactants contained in acrylic resins are concentrated during the film-forming process and accumulate at the interface between particles, or migrate to the interface of the coating layer, reducing the mechanical strength of the coating. However, there may be problems with water resistance and adhesion with laminates. In such a case, a Φ-weighted material containing no surfactant can be used by so-called soap-free weighting.

The method for producing acrylic resin that does not contain surfactants is as follows:
Edited by the Management Development Center Publishing Department, published by the Management Development Center Publishing Department in January 1960, page 309 of ``Water-soluble Polymers/Water-Dispersible Resin Comprehensive Technical Data Collection'' or sponsored by the Industrial Technology Research Group, ``~Latest Research Results. ``Looking forward to the future ~ New developments in emulsions and future technical issues'' lecture text (1973)
You can use the method shown in ``11jA, 2015''. For example, introduction of hydrophilic groups into polymers by using oligomers or high-grade surfactants instead of low-molecular-weight surfactants, or by using a porcelain initiator such as potassium persulfate or ammonium persulfate. Copolymerization of monomers with, utilization of reactive surfactants 1 dispersion particles.

So-called shells with different compositions of the inner and outer layers of
A core type polymer or the like can be used as a production technique for a water-dispersible acrylic resin that does not contain a so-called surfactant Z.

The water-soluble or water-dispersible polyester resin having a sulfonic acid group used in the present invention (hereinafter abbreviated as polyester resin) has excellent coating properties on a polyester film and interlayer adhesion between the coating layer and the polyester film. , cohesive failure property of the coating layer and J1! Effective in improving abrasion resistance, etc. As a polyester resin,
I? -1IO173, JP-A-50-Z3DA-97, and special polyesters can be used.

For example, dicarboxylic acid components of polyester include terephthalic acid, isophthalic acid,
Examples of aliphatic dicarboxylic acids include adipic acid, azelaic acid, sebacic acid and their ester-forming derivatives, and oxymonocarboxylic acids. Examples include oxybenzoic acid and its ester-forming derivatives.

Further, as the glycol component of the polyester, aliphatic, alicyclic, aromatic diols, etc. can be used, and examples thereof include ethylene glycol, i, 1I--f tanediol,
diethylene glycol, triethylene glycol, /
J-Cyclohexane dimetatool, p-xylene diol, and so-called polyethylene glycol are used as examples of poly(oxyalkylene) glycols.

Polypropylene glycol, polytetramethylene glycol, etc. are used.

As the polyester, not only the saturated linear polyester consisting of the above-mentioned ester-forming components, but also polyester consisting of a compound having three or more ester-forming components or polyester having a reactive unsaturated group can be used.

A polyester having a sulfonic acid group can be produced by using a compound having a sulfonic acid group that can be a polyester component together with the above-mentioned polynisder-forming component.

Examples of compounds having sulfonic acid groups include metal salts such as sulfoisophthalic acid, sulfoterephthalic acid, sulfonaphthalene, 6-dicarboxylic acids and their ester-forming visiting conductors.

Preferred metal salts for the gold stripes include lithium, sodium, potassium, and magnesium. A very preferred compound among these is j-sodiosulfoisophthalic acid or S-diosulfodimethyl inphthalate.

Another method for introducing sulfonic acid groups into polyester is to sulfonate the unsaturated groups of polyester, which is an ester-forming aliphatic unsaturated compound as a copolymerization component, with a sulfonating agent such as sodium bisulfite or sodium metabisulfite. Methods can also be exemplified.

The aromatic dicarboxylic acid 1° in the dicarboxylic acid component of the polyester resin preferably ranges from SO mol% to lθO mol%. This is to raise the softening point of the polyester resin and make it less sticky.

The sulfonic acid group in the polyester resin must be present in an amount necessary to make the resin water-bathable or water-dispersible. It is preferable to use

- If the amount of sulfonic acid base is less than the molar ratio, the water solubility or water dispersibility will be insufficient, and if the amount of sulfonic acid base is higher than the molar ratio, the water resistance of the undercoat layer after coating will be poor, or the film will absorb moisture and become mutually unstable. This is because it sticks to the surface.

Furthermore, as a polyester resin, not only the saturated linear polyester consisting of the above-mentioned ester-forming component but also 3
A polyester made of a compound having an ester-forming component having a higher value than the polyester or a polyester lacking a reactive unsaturated group can also be used.

The ratio of polyester resin to the total amount of acrylic resin and polyester resin is 3 to 3, including solid content weight.
The amount of gOM is preferably %, more preferably 5 to 60% by weight. If the polyester resin has a low 3N content, the applicability of the cleaning agent to the base polyester film and the interlayer adhesion are reduced, and the mechanical properties of the coated layer are also reduced. When the amount of polyester resin is more than the go weight ratio, slipperiness and adhesion properties tend to decrease. however,
When the proportion of the polyester resin increases, the slipperiness and adhesion properties can be improved by increasing the amount of silica sol blended.

The silica sol in the present invention refers to "polymer processing", /9
Generally, it is produced by removing alkali ions from sodium silicate, as shown in 1971, Vol. 23, pp. 1F9-1SS. Silica sol that does not contain impurities can be used, but since agglomeration tends to occur and the colloidal state is unstable, silica sol that has a surface stabilized with sodium ions, aluminum ions, ammonium ions, etc. is preferable. Commercially available products include Snowtex (product name) from Nissan Chemical Industries, Ltd.
, Cataloid (product name) of Catalysts & Chemicals Co., Ltd., d
u Pant's Ludo! (Product name), Na1co
Nalcoag (product name) from Chem-iaa1
, 5ytore (product name) manufactured by Monaanto, etc. can be used. Furthermore, as the silica sol of the present invention, a powder obtained by vapor-phase pyrolysis of silicon tetrachloride and dispersed in water may be used, such as Aerosil (trade name) manufactured by Nippon Aerosil Co., Ltd. The particle size of silica sol is S~1
It may be appropriately selected within the range of 00 mμ depending on the thickness of the coating layer and the intended use. The content of silica sol in the coating layer is
Preferably, the amount is 1 to 30% by weight based on the total solid content. If the amount of silica sol is less than 1% by weight, improvements in charging properties, slipperiness, adhesion, etc. are insufficient, and if the amount of silica sol is 30% by weight, frictional abrasion properties deteriorate and white powder is generated. It becomes easier to do.

The method for applying a coating agent to polyester film is written by Yuji Harasaki, published by Maki Shoten in 1979.

A reverse roll coater, a gravure coater, a rod coater, an air doctor coater, or any other coating device shown in "Coating method" can be used.

The coating step may be performed simultaneously or sequentially during the manufacturing process of the biaxially oriented polyester film, and may be applied to the biaxially oriented polyester film product. Particularly preferably, an aqueous dispersion or an aqueous solution is coated on a uniaxially stretched polyester film by a roll stretching method, and the polyester film is immediately stretched in a direction perpendicular to the previous stretching direction, with appropriate drying or without drying. This is a method in which the film is stretched and heat treated (coating stretching method). According to this method,
The coating layer can be dried simultaneously with stretching, and the thickness of the coating layer can be increased regardless of the stretching ratio.

The thickness of the coating layer of the biaxially stretched polyester film of the present invention is preferably in the range of 0.0/μ to lμ, more preferably in the range of θ0/μ to Q/μ.゛ - - Trend: When the thickness of the coating layer is θ0/μ0/μ, it is difficult to apply it uniformly, so uneven coating occurs on the product.If it is thicker than 7μ, the slipperiness decreases.

The coating layer of the biaxially stretched polyester film of the present invention includes:
If necessary, adhesion improvers, antifoaming agents, coating improvers, thickeners, ultraviolet absorbers, antioxidants, antistatic agents, lubricants, inorganic fine particles, dyes, pigments, etc. may be added. From 0
Furthermore, since the coating agent is water-based, the coating layer can contain water-soluble or water-dispersible epoxy resins, silicone resins, vinyl resins, urethane resins, polyamide resins, butadiene resins, and the like. In addition, to improve the adhesion, water resistance, solvent resistance, and mechanical strength of the coating layer,
As a crosslinking agent, the coating layer may contain methylolated or alkylolated urea threads, melamine-based, acrylamide-based, polyamide-based resins, etc., epoxy compounds, aziridine compounds, blocked polyisocyanates, vinyl compounds, and silane compounds.

The biaxially oriented polyester film of the present invention has good windability in the i-film process, has excellent surface properties, especially slipperiness, and can be used as a lμ to SOOμ film for packaging materials, insulating materials, photosensitive materials, drafting materials, etc. materials, electrophotographic materials,
It is useful as a base material for magnetic recording materials, and is particularly useful as a base material for compact magnetic recording materials that require smoothness.

Hereinafter, the present invention will be explained without mentioning examples. Note that the evaluation in the examples is based on the method described in the first section.

+13 Workability Layer approximately 30 sheets of 2 At film and observe the overall flexibility, peelability, pullability, and chargeability of each film +2) *Friction coefficient: 23℃, Ao multilayer, /DO ”?/
Value when the stacked films are translated in parallel for 7 minutes under a1 load (3) High temperature friction coefficient gr with a load of 10f applied to one end
Fixing a film with a width of Ia at 6 degrees φ and a value S (4) Adhesion between the coating layer and the base film: Observation of the surface condition by rapid peeling test using a serotonave (5) Adhesion: + OC, θ excellent RE, /θkg /
cl.

ASTM D/19 for film laminated under 20 hour conditions
Peel strength by method 3 (6) Transferability of coating agent: Film and film, film and chrome-plated metal plate, and film and polyester film were layered with the cobalt-nickel magnetic layer deposited on top of each other under the same conditions as the adhesion test. After the pressure test, observation of the surface of the test material using a microscope (7) Stylus type surface roughness: Koita Research Institute, thin film step meter ET-/θ type, stylus tip half type a5μ, stylus load/p Measured with Comparative Example 1 Approximately 2g of polyethylene terephthalate with an intrinsic viscosity of 06, which contains almost no surface protrusion-forming agent based on polymerization catalyst residue, etc.! It was melted at C and extruded onto a cooling drum at about 60° C. while applying electrostatic charge. Further, the film was stretched 2S times in the longitudinal direction at 3° C., then stretched in the transverse direction at 10° C., and heat-treated and fired at 220° C. to obtain a biaxially stretched film having a thickness of 1 to 1 μ. This film had extremely poor windability, making it difficult to obtain a long film roll, and the resulting film roll had a poor winding appearance, making it impossible to ship as a product. Just in case, I cut it out as an A-da version and tried it out, but the films stuck together and became one whole, making it difficult to handle the film. What is the coefficient of friction of this film?

Measurement could not be performed because the film did not slip. The single-layer film could not be put to practical use due to its lack of slipperiness.

Comparative example The main components are comethyl methacrylate, inbutyl methacrylate, acrylic acid, methacrylic acid, and glycidyl methacrylate, and the carboxylic acid group is neutralized with ammonia, and the amount of ammonium base in the carboxylic acid is increased to make it water-soluble. Self-crosslinking acrylic resin containing no surfactant (Jurimar AT-M9/manufactured by Nippon Cotton Yakubushiki Company)
t, trade name) io part (hereinafter sometimes abbreviated as "1 solid content"), Cumolti in the dicarboxylic acid is 5-sodiosulfoisophthalic acid, and in addition, from terephthalic acid, isophthalic acid, ethylene glycol, diethylene glycol. A water-dispersible polyester resin that does not contain a surfactant (Polyester-WR?O/manufactured by Nippon Kaisei Kagaku Kogyo Co., Ltd.)
, trade name) and 125 parts of lithium salt of perfluoroalkyl sulfonic acid at a concentration of 3 weight - the same as in Comparative Example 1, except that a water-based coating agent with an orange concentration of 3 weight was applied to one side of the film after longitudinal stretching and before transverse stretching. A biaxially stretched polyester film was obtained. The thickness of the coating layer is approximately aoqii' as solid content.
/ m”.

In general, water-dispersible acrylic resins contain coarse particles or agglomerated particles, which may require precision filtration depending on the application or cause problems such as agglomeration during the coating process. The acrylic resin is water-soluble and is therefore advantageous in forming precise surface conditions.

However, the film obtained in this comparative example was flat and had strong adhesion to each other due to static electricity, and was inferior to the film of comparative example 1, which did not cover the coating layer, in terms of workability. Ta.

Examples 1 to 3 The amounts of the same acrylic resin used in Comparative Example C were 70 parts, 45 parts, and 60 parts, respectively, and correspondingly, 10 parts ( Example t), 15 parts (Example co), 20 parts (Example 3)
) A biaxially oriented polyester film was obtained by applying the same water-based coating agent as in Comparative Example to the film in the same manner as in Comparative Example, except that the same water-based coating agent was used as in Comparative Example. This film has good transparency, no charging property, and despite the formation of minute surface protrusions, the first
As shown in the table, it was a good film. The winding property and winding appearance in the film forming process were also good. The surface roughness was also suitable for precision applications.

Example 1I-6 Instead of the silica sol of Examples 1 to 3, particle size 11'0-
5 parts each of silica sol of j Omμ (Example)
, io parts (Example S), and 20 parts (Example 6) were used, and correspondingly 7S parts, 70 parts, and 60 parts of acrylic resin were used, respectively, in the same manner as Examples 1 to 3. A biaxially stretched polyester film was obtained. This film had good transparency and was a good film as shown in Table 1. In addition, the high-temperature dynamic friction coefficient at the winding angle and temperature gO ℃ was superior to that of the film of Comparative Example/without a coating layer, which was aS/ on the coating surface of Example Tei. .

Example 7 A biaxially stretched polyester film was obtained in the same manner as in Example D, except that the coating agent of Example≠ was applied to both sides of the film after longitudinal stretching and before coating and stretching. This film showed good properties as shown in Table 1. In addition, this film &
Since the film had a coating layer on both sides, it was more useful in film conveyance processes, etc. than a film with a coating on one side. In addition, in a flat film with a coating layer, oligomer protrusions are formed unevenly over time, which may cause the &1 problem in high-density magnetic recording applications, but this film is a countermeasure for such oligomer problems. It was also useful.

Example g Self-crosslinking No. 1 with a shell-core structure in which methylmate is used as the main component instead of the acrylic resin in Example t, the carboxylic acid group is neutralized with ammonia, and does not contain a surfactant.
A biaxially stretched polyester film was obtained in the same manner as in Example D, except that a hydrosol type acrylic resin (Jurimar-8EK-72!; trade name, manufactured by Nippon Pure Chemical Industries, Ltd.) was used. This film had good properties as shown in Table 1. Compared to the acrylic resin of Example t, the acrylic resin of this example has relatively good slipperiness even without blending silica sol, but the film of this embodiment containing silica sol has even better slipperiness. It demonstrated properties such as slipperiness and adhesion.

As shown in the examples above, the film of the present invention has good windability in the film forming process even if it is flat, and
It has excellent surface properties, especially slipperiness, and is useful in many practical applications.

Continuation of page 1

Claims (1)

[Claims] (1) A coaxially oriented polyester film in which a coating layer consisting of a water-dispersible or water-soluble acrylic resin, a water-dispersible or water-soluble polyester resin having a sulfonic acid group, and silica sol is provided on at least one side of the polyester film.