JP2016113615A - Polyester resin and laminate using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester resin enhancing adhesive strength especially on a coloring layer/polyester resin coated film boundary in a colored release liner on a protective film used for a manufacturing process of electronic components or the like, enhancing discriminability without reducing adhesive strength eve during high temperature processing when manufacturing the protective film, capable of being a release liner which detachment of the coloring agent is suppressed, excellent in balance of adhesive strength and heat resistance and having enhanced adhesive strength to the coloring layer.SOLUTION: There is provided a polyester resin having hydroxyl group value of 3 to 30 mgKOH/g and glass transition temperature (Tg) of less than 40°C and containing isophthalic acid of 10 to 70 mol%, aliphatic acid dicarboxylic acid having 6 to 12 carbon atoms of 10 to 50 mol% and oxycarboxylic acid of 5 to 30 mol% as acid components constituting the polyester resin. There is provided a polyester resin consisting of a polyester resin (a) having Tg of less than 0°C and a polyester resin (b) having Tg of 0 to less than 40°C with (a)/(b)=90/10 to 10/90 (mass ratio).SELECTED DRAWING: None

Description

  The present invention relates to a polyester resin having an excellent balance between adhesive strength and heat resistance.

In recent years, LCD components such as polarizing plates and retardation plates used in liquid crystal displays (hereinafter abbreviated as LCD) including semiconductors, plasma display panel (hereinafter abbreviated as PDP) components, organic electroluminescence (hereinafter abbreviated as “LCD”). In a component member or the like (abbreviated as “organic EL”), a protective film on the member surface is often used in order to prevent breakage or damage in the manufacturing process.
Such a protective film is coated with an adhesive, and the adhesive surface is protected with a release liner until just before being used as a protective film. A film colored in white or the like is used in order to improve the distinguishability of the release liner and make it easy to detect defective pasting or forgetting to peel off.
As the structure of the release liner colored in white, it is used in a laminated structure of a liner substrate / release layer made of a white PET film or a laminated structure of a liner substrate / white printed layer / release layer made of a transparent PET film. (For example, Patent Document 1).

JP 2009-263400 A

The inventors of the present invention have found that the structure of the release liner described in Patent Document 1 has the following problems.
That is, when the release liner is peeled from the protective film, the printed layer is detached together with the release layer from the liner base material, and there is a problem that the surroundings are contaminated by the colorant contained in the printed layer. On the other hand, a white PET film kneaded with a colorant is expensive and has a high economic burden.
As a method for suppressing the release of the colorant, in the liner substrate / printing layer, another substrate is further laminated on the printing layer, and the printing layer is completely sandwiched between the two substrates so that the printing layer It is conceivable to suppress the detachment of the colorant from the toner. However, it was difficult to bond another substrate with sufficient adhesion to the printed layer. For example, a polyester resin-based adhesive as described in JP-A-4-164957 and JP-A-2004-123980 is used, such as liner base material / printing layer / adhesive layer / base material / release layer. In the case of the configuration, there is a problem that peeling easily occurs between the printing layer / adhesive layer.
Furthermore, when a protective film is laminated on the release liner having the above-described configuration via an adhesive layer, the adhesive force between the print layer / adhesive layer of the release liner is lowered and peeled off due to high temperature processing. It was.

  An object of this invention is to obtain the polyester resin which was excellent in the balance of adhesive strength and heat resistance, and improved especially the adhesive strength with respect to a colored layer.

As a result of intensive studies to solve the above problems, the present inventor has reached the present invention.
That is, the gist of the present invention is as follows.
(1) A polyester resin having a hydroxyl value of 3 to 30 mgKOH / g and a glass transition temperature of less than 40 ° C. As an acid component constituting the polyester resin, 10 to 70 mol% of isophthalic acid and an aliphatic dicarboxylic acid having 6 to 12 carbon atoms A polyester resin containing 10 to 50 mol% of acid and 5 to 30 mol% of oxycarboxylic acid.
(2) The polyester resin comprises a polyester resin (a) having a glass transition temperature of less than 0 ° C. and a polyester resin (b) having a glass transition temperature of 0 ° C. or more and less than 40 ° C., and (a) / (b) = 90 / The polyester resin according to (1), which is 10 to 10/90 (mass ratio).
(3) A resin solution obtained by dissolving the polyester resin of (1) or (2) in an organic solvent.
(4) The resin solution of (3) further containing a curing agent.
(5) The resin solution of (4), wherein the curing agent is isophorone diisocyanate.
(6) A film obtained from the resin solution of (3) to (5).
(7) Laminated body laminated in order of (first base material) / (colored layer) / (film of (6)) / (second base material).
(8) The method for producing a laminate according to (7), wherein the first base material on which the colored layer is formed and the second base material on which the film of (6) is formed are bonded together.

According to the present invention, it is possible to obtain a polyester resin that is excellent in the balance between adhesive strength and heat resistance, and particularly improved in adhesive strength to the colored layer. Such a polyester resin is not only improved in the adhesive strength at the colored layer / polyester resin coating interface in the release liner of the protective film used in the manufacturing process of electronic parts, but also processed at a high temperature during the production of the protective film. Even in such a case, since the adhesive strength does not decrease, it is possible to obtain a release liner with improved discrimination and suppressed colorant detachment.

Hereinafter, the present invention will be described in detail.
The polyester resin of the present invention comprises isophthalic acid, an aliphatic dicarboxylic acid having 6 to 12 carbon atoms, and oxycarboxylic acid as essential components as an acid component constituting the polyester resin.
As an acid component which comprises a polyester resin, it is necessary to contain 10-70 mol% of isophthalic acid with respect to a total of 100 mol% of an acid component, It is preferable to contain 20-50 mol%, It contains 30-40 mol% It is more preferable. When the content of isophthalic acid is less than 10 mol%, the adhesive strength is lowered, and when it exceeds 70 mol%, the heat resistance is lowered.

  Moreover, as an acid component which comprises a polyester resin, it is necessary to contain 10-50 mol% of C6-C12 aliphatic dicarboxylic acid with respect to a total of 100 mol% of an acid component, and 10-40 mol% is contained. The content is preferably 10 to 30 mol%, and more preferably 10 to 30 mol%. When the aliphatic dicarboxylic acid having 6 to 12 carbon atoms is less than 10 mol%, the adhesive strength is lowered, and when it exceeds 50 mol%, the heat resistance is lowered. The aliphatic dicarboxylic acid having 6 to 12 carbon atoms is not particularly limited, but adipic acid (carbon number 6), azelaic acid (carbon number 9), sebacic acid (carbon number 10), dodecanedioic acid (carbon number) 12) etc. are mentioned preferably.

The oxycarboxylic acid is a component having both the properties of an acid component and a glycol component, and lactones are also included in the oxycarboxylic acid. Such components include lactic acid, glycolic acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxyisobutyric acid, 2-hydroxy-2-methylbutyric acid, 2-hydroxyvaleric acid, 3- Hydroxyvaleric acid, 4-hydroxyvaleric acid, 5-hydroxyvaleric acid, 6-hydroxycaproic acid, 10-hydroxystearic acid, 4- (β-hydroxy) ethoxybenzoic acid, β-propiolactone, β-butyrolactone, γ -Aliphatic oxycarboxylic acids such as aliphatic lactones such as butyrolactone, δ-valerolactone, ε-caprolactone, salicylic acid, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, vanillic acid, syringic acid, protocatechuic acid, orthothelic acid, Gallic acid, mandelic acid, benzylic acid, caffeic acid, ferulic acid, sinapine , Coumarin, psoralen, angelicin, aromatic oxycarboxylic acids aromatic lactones such as bergapten.
Of these, aliphatic oxycarboxylic acids are preferable from the viewpoint of not only polymerizability but also adhesive strength and heat resistance, and further, aliphatic oxycarboxylic acids having no side chain that can maintain adhesive strength and heat resistance in a highly balanced manner. Carboxylic acid is more preferred. Examples of the aliphatic oxycarboxylic acid having no side chain include glycolic acid, 4-hydroxybutyric acid, 6-hydroxycaproic acid, γ-butyrolactone, δ-valerolactone, ε-caprolactone, and the like, among them ε-caprolactone. Is most preferred.

  The oxycarboxylic acid needs to be contained in an amount of 5 to 30 mol%, preferably 10 to 25 mol%, more preferably 15 to 20 mol%, based on the entire polyester resin. If the content of oxycarboxylic acid is less than 5 mol%, the adhesive strength is lowered.

  Other acid components used in the polyester resin of the present invention are not particularly limited. For example, terephthalic acid, isophthalic acid, malonic acid, succinic acid, glutaric acid, pimelic acid, suberic acid, undecanedioic acid, tridecanedioic acid, Tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, heptadecanedioic acid, octadecanedioic acid, nonadecanedioic acid, eicosanedioic acid, docosanedioic acid, phthalic acid, naphthalenedicarboxylic acid, 4, 4'-dicarboxybiphenyl, 5- Sodium sulfoisophthalic acid, 5-hydroxy-isophthalic acid, fumaric acid, maleic acid, itaconic acid, mesaconic acid, citraconic acid, 1,3,4-benzenetricarboxylic acid, 1,2,4,5-benzenetetracarboxylic acid, Pyromellitic acid, trimellitic acid, oxalic acid, 1,4-cyclohexanedi Examples thereof include carboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 2,5-norbornene dicarboxylic acid, dimer acid, hydrogenated dimer acid, and the like, or anhydrides thereof. Among these, terephthalic acid and isophthalic acid are preferably included from the viewpoint of durability and the like. These may be used alone or in combination of two or more.

  Examples of the glycol component used in the polyester resin of the present invention include ethylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,5-pentanediol, 1,7-heptanediol, and 1,8-octane. Diol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,2-cyclohexanedimethanol, tricyclode Candimethanol, spiroglycol, dimerdiol, neopentylglycol, 2,2-butylethylpropanediol, 1,2-propanediol, 2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 1 , 4-phenylene glycol, 1,4-pheny Ethylene oxide adducts of glycol, propylene oxide adducts of 1,4-phenylene glycol, ethylene oxide adduct of bisphenol A, propylene oxide adduct of bisphenol A, polyalkylene glycol, and the like. Among these, ethylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, ethylene oxide adduct of bisphenol A, and polyalkylene glycol are preferable. These may be used alone or in combination of two or more.

  When 1,4-butanediol or 1,6-hexanediol is used as the glycol component constituting the polyester resin, it is preferably contained in an amount of 5 to 80 mol% with respect to 100 mol% in total of the glycol components. It is more preferable to contain 80 mol%, it is more preferable to contain 30-80 mol%, and it is further more preferable to contain 40-80 mol% or more. If the content of 1,4-butanediol or 1,6-hexanediol is less than 5 mol%, the crystallinity may be lowered and heat resistance may be lowered, and if it exceeds 80 mol%, the crystallinity is increased. Too much adhesive strength may be reduced.

  When the ethylene oxide adduct of bisphenol is used as the glycol component constituting the polyester resin, it is preferably contained in an amount of 0.1 to 10 mol% with respect to 100 mol% in total of the glycol components. When the ethylene oxide adduct of bisphenol is less than 0.1 mol%, the heat resistance is lowered, and when it exceeds 10 mol%, the adhesive strength is lowered. As bisphenol, bisphenol A, bisphenol F, and bisphenol S are preferably used, and bisphenol A is particularly preferable.

When polyalkylene glycol is used as the glycol component constituting the polyester resin, it is preferably contained in an amount of 0.1 to 10 mol%, more preferably 0.5 to 7 mol%, based on a total of 100 mol% of the glycol components. More preferably, it is more preferable to contain 1-4 mass%. When the polyalkylene glycol is less than 0.1 mol%, the adhesive strength is lowered, and when it exceeds 10 mol%, the heat resistance is lowered.
The polyalkylene glycol is not particularly limited, and examples thereof include diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, polytetramethylene glycol, and polypropylene glycol. Among these, triethylene glycol, polyethylene glycol, and polytetramethylene glycol are preferable.

  Moreover, monocarboxylic acid and monoalcohol may be copolymerized with the polyester resin. Examples of monocarboxylic acids include lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, benzoic acid, p-tert-butylbenzoic acid, cyclohexane acid, 4-hydroxyphenyl stearic acid, and the like. Examples of the alcohol include octyl alcohol, decyl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, and 2-phenoxyethanol.

  The hydroxyl value of the polyester resin of the present invention is required to be 3 to 30 mgKOH / g, preferably 4 to 20 mgKOH / g, and more preferably 5 to 10 mgKOH / g. When the hydroxyl group is less than 3 mgKOH / g, the heat resistance is lowered, and when it exceeds 30 mgKOH / g, the adhesive strength tends to be lowered.

  The glass transition temperature of the polyester resin of the present invention needs to be less than 40 ° C, preferably less than 20 ° C, more preferably less than 0 ° C, and most preferably less than -10 ° C. Adhesive strength falls that a glass transition temperature is 40 degreeC or more. The lower limit of the glass transition temperature is not particularly specified, but is preferably −50 ° C. or higher, and more preferably −40 ° C. or higher. When the glass transition temperature is lower than −50 ° C., the dynamic friction coefficient μk of the resulting coating tends to increase.

  The polyester resin of the present invention preferably has a number average molecular weight of 4,000 to 30,000, more preferably 5,000 to 25,000, and further preferably 6,000 to 20,000. When the number average molecular weight is less than 4000, the cohesive force tends to decrease and the adhesive strength tends to decrease. When the number average molecular weight exceeds 30000, the solution viscosity of the resin solution increases, and not only the handling property decreases, but also the static friction coefficient μs of the resulting film. Tend to decrease.

Next, a method for producing a polyester resin will be described.
After the necessary raw materials are put into the reaction vessel, the esterification reaction is performed for 4 hours or more at a temperature of 180 ° C. or higher, and then polycondensed by a known method. For example, under a reduced pressure of 130 Pa or lower The polyester resin can be obtained by proceeding the polycondensation reaction at a temperature of 220 to 280 ° C. until the desired molecular weight is reached.

In esterification and polycondensation reactions, titanium compounds such as tetrabutyl titanate, metal acetates such as zinc acetate, magnesium acetate, and zinc acetate, antimony trioxide, hydroxybutyltin oxide, tin octylate, etc. Polymerization can be carried out using the organotin compound. In this case, the amount of catalyst used is preferably 0.1 to 20 × 10 ⁻⁴ mol per 1 mol of the acid component.

  In addition, after the polycondensation reaction is completed, a predetermined amount of a polybasic acid component or an anhydride thereof is added and reacted to modify the terminal hydroxyl group to a carboxyl group or to a carboxyl group in the molecular chain by transesterification. The acid value can be moderately imparted by introducing.

  A flame retardant can be added to the polyester resin of the present invention as needed, but is not limited thereto. Examples of the flame retardant include, but are not limited to, decabromodiphenyl ether, bis (pentabromophenyl) ethane, tetrabromobisphenol, hexabromocyclododecane, hexabromobenzene and other halides, triphenyl phosphate, triphenyl Cresyl phosphate, 1,3-phenylenebis (diphenyl phosphate), phosphorous compounds such as ammonium polyphosphate, polyphosphoric acid amide, guanidine phosphate, halogen-containing phosphate esters such as tris (chloroethyl) phosphate, tris (dichloropropyl) phosphate, red Phosphorus, nitrogen flame retardants such as triazine, melamine isocyanurate, ethylene dimelamine, inorganic flame retardants such as tin dioxide, antimony pentoxide, antimony trioxide, aluminum hydroxide, magnesium hydroxide Aid, there is a such as silicone powder. In order to reduce the environmental load, it is preferable to select a flame retardant from the viewpoint of non-halogen, non-phosphorus, and deuterated metal.

  The polyester resin of the present invention can be mixed with two kinds of resins having different glass transition temperatures as necessary so that sufficient adhesive strength can be exhibited even when heat-sealing at low temperatures while maintaining heat resistance. . That is, it can be a mixture of a polyester resin (a) having a glass transition temperature of less than 0 ° C. and a polyester resin (b) having a glass transition temperature of from 0 ° C. to less than 40 ° C. In that case, (a) / (b) = 90/10 to 10/90 (mass ratio) is preferable.

  The polyester resin (a) must have a glass transition temperature of less than 0 ° C, preferably less than -10 ° C, and more preferably less than -20 ° C. When it exceeds 0 degreeC, adhesive strength will fall.

  The polyester resin (a) may be amorphous or crystalline, but is preferably a crystalline resin from the viewpoint of heat resistance.

  Next, the polyester resin (b) needs to have a glass transition temperature of 0 ° C. or higher and lower than 40 ° C. When the glass transition temperature is less than 0 ° C., the heat resistance decreases, and when the glass transition temperature is 40 ° C. or more, the adhesive strength may decrease.

  The polyester resin (b) is preferably an amorphous resin from the viewpoints of solubility in a solvent and adhesive strength.

  Furthermore, in the polyester resin of the present invention, if necessary, heat stabilizers such as phosphoric acid and phosphate esters, hindered phenol compounds, hindered amine compounds, antioxidants such as thioether compounds, lubricants such as talc and silica, Conventionally known additives such as pigments such as titanium oxide, zinc oxide, and carbon black, fillers, antistatic agents, and foaming agents may be included.

  Since the polyester resin composition forms a film, it can be dissolved in an organic solvent or the like and used as a resin solution.

  The polyester resin of the present invention may be crystalline or amorphous, and may be dissolved in an organic solvent at a solid content concentration of 20% by mass or more, preferably 20 to 50% by mass, and preferably 25 to 40%. It is preferable that it is mass%. The organic solvent to be used is not particularly limited. For example, aromatic solvents such as toluene, xylene, solvent naphtha and solvesso, ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, methyl alcohol, ethyl alcohol, isopropyl alcohol and isobutyl alcohol And alcohol solvents such as ethyl acetate and normal butyl acetate, acetate solvents such as cellosolve acetate and methoxyacetate, or a mixture of two or more of these solvents.

  Even when the polyester resins (a) and (b) are mixed and used as the polyester resin, it can be dissolved in an organic solvent by the same method as described above to obtain a resin solution. When using the polyester resin (a) and the polyester resin (b), a method in which each is weighed in a predetermined amount and simultaneously dissolved in an organic solvent, or separately weighed and dissolved in an organic solvent, and then the respective resin solutions are added. Although the method of mixing etc. is mentioned, it does not specifically limit.

  The solution viscosity of the resin solution is preferably 10000 mPa · s or less, more preferably 5000 mPa · s or less, and further preferably 3000 mPa · s or less when measured at 25 ° C. with a B-type viscometer. Most preferably, it is 1000 mPa · s or less. When it exceeds 10,000 mPa · s, it becomes a viscous resin solution and is difficult to handle.

The resin solution of the present invention can further contain a curing agent.
Curing agents that can be used are aliphatic or alicyclic isocyanates, such as hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, diphenylmethane diisocyanate, and burette types of these isocyanates. , Cyanurate type, and adduct type polyisocyanates, among which isophorone diisocyanate, hexamethylene diisocyanate, or their polyisocyanate type is preferably used.

  It is preferable that content of a hardening | curing agent is 1-30 mass parts with respect to 100 mass parts of polyester resins, It is more preferable that it is 1-10 mass parts, It is further more preferable that it is 1-5 mass parts. . If the content of the curing agent is less than 1 part by mass, it does not contribute to heat resistance, and if it exceeds 30 parts by mass, the adhesive strength decreases, and further, the polyester resin cures and shrinks, generating wrinkles on the substrate surface, and the appearance May be damaged.

An example of obtaining the laminate of the present invention will be described below.
Although a laminated body is not limited to the following illustration, in order to demonstrate the aspect of this invention most preferably, it demonstrates taking a protective film with a release liner as an example.
First, the release liner forms a colored layer on the liner base material (hereinafter referred to as the first base material) (Step 1), and another base material different from the liner base material (hereinafter referred to as the second base material). ) (Step 2), the first base material on which the colored layer is formed and the second base material on which the film is formed (first base material) ) / (Colored layer) / (film) / (second substrate) in order of thermocompression bonding of the (colored layer) / (film) interface (step 3). In addition, it is preferable that the peeling layer, such as a silicone layer, is provided in advance on the opposite surface of the second substrate on which the film is formed.
On the other hand, the second substrate surface of the release liner is bonded to one side of a separately prepared protective film substrate while forming an adhesive layer (step 4), thereby releasing the [release liner] {(first 1 base material) / (colored layer) / (film) / (second base material) / (release layer)} / [protective film] {(adhesive layer) / (protective film base material)} Can do.

  The colored layer in Step 1 can be formed by applying a colored resin comprising a colorant and a binder component to the first substrate by a known method.

  As the colorant, known ones can be used, and titanium oxide, zinc oxide, carbon black, iron oxide, bitumen, ultramarine, aluminum powder, bronze powder, mica titanium powder, etc. are concealing, weather resistance, dispersibility. In view of the above, titanium oxide and carbon black are preferable because of their excellent concealability. Inorganic particles such as calcium carbonate, barium sulfate, kaolin, and talc may be mixed as extender pigments with the inorganic particles.

  The content of the colorant may be adjusted as appropriate, but is preferably 1 to 10 parts by weight, more preferably 2 to 9 parts by weight, and 3 to 8 parts by weight with respect to 100 parts by weight of the polyester resin. More preferably. When the content of the colorant is less than 1 part by mass, the concealability is inferior, and when it exceeds 10 parts by mass, the dispersibility is lowered or the adhesive strength is impaired.

  As the binder component, resin components such as acrylic, polyester, and urethane can be used. Among them, acrylic resin components are preferable. Moreover, as an acrylic resin binder, that whose glass transition temperature is -40-50 degreeC is preferable. The acrylic resin binder can be produced by a polymerization method such as a solution polymerization method, an emulsion polymerization method, or an ultraviolet irradiation polymerization method.

  Formation of the coating film in the above step 2 can be performed by applying and drying the above resin solution on the second substrate using the following coater.

  As the coater, for example, a bar coater, a comma coater, a slot die coater, a roll coater, a reverse roll coater, a gravure coater, a micro gravure coater, a gravure reverse coater, a flow coater, etc. can be used. Can form a stable film with a low-viscosity resin solution, which is suitable for the above case. It can be arbitrarily selected and controlled depending on the application and film thickness. Moreover, you may apply | coat in multiple times.

  The drying conditions after coating vary depending on the type of resin solution used, the solid content concentration, the coating amount, and the material used in the second substrate. For example, a PET film is used as the second substrate and drying is performed. When a film having a thickness of 5 μm is formed, it can be performed at a temperature in the range of 80 to 130 ° C. for several tens of seconds to several minutes.

  The film obtained from the polyester resin of the present invention can be formed into a film having a specific friction coefficient, which will be described later, by forming the film by the above method. By setting it as such a friction coefficient, in the process 3, the operativity of thermocompression bonding improves.

  The thermocompression bonding conditions vary depending on the type of binder component for forming the colored layer used in step 1, but the thermocompression bonding temperature is preferably 100 ° C. or lower, more preferably 90 ° C. or lower. When an acrylic resin-based binder is used as the binder component, it can be performed at 80 ° C. As a specific method of thermocompression bonding, for example, it can be continuously performed by sandwiching with a heated heat roll using a laminator or the like.

  In the polyester resin of the present invention, the static friction coefficient μs on the surface of the coating formed on the resin base material is preferably 0.5 or more, more preferably 0.7 or more, and further preferably 0.9 or more. preferable. When the static friction coefficient μs is less than 0.5, the initial tackiness is lowered, and the pressure is not sufficiently applied to the adherends in the thermocompression bonding in the step 3, and the adhesive strength is not preferable. In particular, when the colored layer is white, a large amount of colorant such as titanium oxide is contained, so that the adhesive strength tends to be lower than when the colored layer is not formed. Even in such a case, the adhesive strength between the colored layer / coating layer can be increased by applying sufficient pressure between the adherends and thermocompression bonding.

  On the other hand, the difference (μs−μk) between the static friction coefficient μs and the dynamic friction coefficient μk needs to be 0.2 or more, preferably 0.25 or more, more preferably 0.3 or more, and further preferably 0.4 or more. When the difference between the static friction coefficient μs and the dynamic friction coefficient μk (μs−μk) is 0.2 or less, when thermocompression bonding is performed with a roll To roll, blocking occurs or slippage failure occurs with a roll such as a laminator. This is not preferable because the properties are lowered. From the above, the dynamic friction coefficient μk is preferably 0.8 or less, more preferably 0.7 or less, further preferably 0.6 or less, and most preferably 0.5 or less.

  In the present invention, a polyester resin having a predetermined glass transition temperature is used using a predetermined monomer component, and by controlling the number average molecular weight and the like, it becomes easy to form a film having the above friction coefficient. In particular, the dynamic friction coefficient μk tends to be reduced by setting the glass transition temperature to a predetermined value. By controlling the number average molecular weight, the surface smoothness of the resulting coating can be changed and the static friction coefficient μs can be adjusted. . Therefore, by performing the above adjustment, the dynamic friction coefficient μk is not increased while increasing the static friction coefficient, and the difference (μs−μk) between the static friction coefficient μs and the dynamic friction coefficient μk can be controlled within a predetermined range.

  As described above, the operability of thermocompression bonding is improved in step 3 by controlling the static friction coefficient and the dynamic friction coefficient of the resulting coating. Specifically, the static friction coefficient is increased and the initial tackiness of the coating is increased, whereby a sufficient pressure is applied to the adherends at the time of thermocompression bonding, and the adhesive strength is improved. Moreover, when a dynamic friction coefficient reduces, especially when performing thermocompression bonding with the roll To roll, blocking can be produced or the slip failure with a roll can be suppressed.

Further, after step 3, in step 4, the release liner and the protective film are bonded together to obtain a protective film with a release liner. Illustrating the specific flow of step 4, for the second substrate surface of the release liner obtained in step 3, preferably, for the release layer surface of the second substrate on which the release layer is formed, An adhesive layer is formed. The adhesive layer can be formed using a known adhesive, for example. An acrylic adhesive or a rubber adhesive is used. The pressure-sensitive adhesive solution is applied using a laminator or the like so that the thickness of the pressure-sensitive adhesive layer after drying is about 10 to 30 μm, and the protective film substrate is thermocompression bonded to the pressure-sensitive adhesive layer.
However, when heat processing is performed again by the thermocompression bonding in the step 4, peeling (delamination) may occur between the colored layer / film adhered in the step 3.
The coating obtained by the present invention has heat resistance that does not cause a decrease in adhesive strength even in such a case.

  The polyester resin of the present invention has an excellent balance between adhesive strength and heat resistance, and particularly has improved adhesive strength for the colored layer. Such a polyester resin can be used as various coatings, and can be suitably used, for example, as an adhesive used for bonding printed substrates. In particular, in order to improve concealability, it is possible to suppress a decrease in adhesive strength to a colored layer highly filled with an inorganic pigment, and further, a decrease in adhesive strength at the time of heating, so that it can be used as a laminate of various decorative sheets. Especially, it can use suitably with a release liner, a flexible flat cable, etc.

The present invention will be specifically described below with reference to examples.
In addition, about each characteristic of (1)-(5), it measured or analyzed using either single polyester resin or the mixed resin which consists of 2 types of polyester resins. For the mixed resin, a sufficiently mixed one was used.

1. Evaluation Method (1) Number Average Molecular Weight of Polyester Resin or Mixed Resin Unit (Shimadzu Corporation, “LC-10ADvp Type”) and Ultraviolet-Visible Spectrophotometer (Shimadzu Corporation, “SPD-6AV Type”) ) And GPC analysis. The analysis conditions were a detection wavelength of 254 nm, tetrahydrofuran was used as a solvent, and the measurement was performed in terms of polystyrene.

(2) Glass transition temperature of polyester resin or mixed resin According to JIS-K7121, an input compensation type differential scanning calorimeter (“Diamond DSC type” manufactured by Perkin Elmer, detection range −50 ° C. to 200 ° C.) is used. The measurement was performed under the condition of a temperature rising rate of 10 ° C./min, and an intermediate value between two bending point temperatures derived from the glass transition in the obtained temperature rising curve was obtained, and this was taken as the glass transition temperature. In addition, about what can detect two glass transition temperatures, the lower value was made into the glass transition temperature of this polyester resin or mixed resin.

(3) Copolymerization composition of polyester resin or mixed resin Using a NMR measurement apparatus (“JNM-LA400 type” manufactured by JEOL Ltd.), ¹ H-NMR measurement is performed, and the composition is determined from the peak intensity of each copolymer component. Asked. Note that deuterated trifluoroacetic acid was used as a measurement solvent.

(4) Acid value of polyester resin or mixed resin 0.5 g of dioxane / water = 9/1 (volume ratio) mixed solvent was added to the sample and heated to reflux, then cresol red was used as an indicator and 0.1N-KOH methanol solution. The acid value was determined by titration.

(5) Hydroxyl value of polyester resin or mixed resin Add acetic anhydride and pyridine to 3 g of sample and heat to reflux, then add distilled water to heat to reflux, add dioxane, and heat to reflux. With Cresol Red / Thymol Blue as an indicator,
The solution was titrated with a 0.5N KOH methanol solution to determine the hydroxyl value.

(6) Production of resin film-forming film Polyester resins (a) and (b) obtained in the production examples described later were used. Mixing the polyester resin (a) alone or the polyester resins (a) and (b) in a predetermined ratio, mixing the toluene and methyl ethyl ketone in a mass ratio of 8: 2 so that the resin solids concentration is 20% by mass. A solvent was added, and the solution was sealed and dissolved with a paint shaker to obtain a resin solution. Moreover, the hardening | curing agent was mixed as needed.
The obtained resin solution is coated on a corona-treated surface of a biaxially stretched PET film (manufactured by Unitika, thickness 50 μm) with a tabletop coating device (film applicator manufactured by Yasuda Seiki Co., Ltd .; No. 542-AB, bar coater) Then, it was dried with hot air at 120 ° C. for 1 minute to form a resin film having a thickness of 5 μm, and heat-treated at 40 ° C. for 72 hours.

(7) Preparation of colored layer forming film The solid content ratio is 50% by mass with respect to the acrylic resin solution (“Acridic A-165” manufactured by DIC, non-volatile content 45% by mass, solvent; toluene, n-butanol). Thus, titanium oxide (manufactured by Ishihara Sangyo Co., Ltd.) was added and stirred with a homodisper to obtain a colored solution.
Using the above-mentioned colored solution on a corona-treated surface of a biaxially stretched PET film (manufactured by Unitika, thickness 50 μm), a tabletop coating apparatus (film applicator manufactured by Yasuda Seiki Co., Ltd .; No. 542-AB type, equipped with a bar coater) After coating, the substrate was dried with hot air at 120 ° C. for 2 minutes to form a colored layer having a thickness of 1 μm and heat-treated at 40 ° C. for 72 hours.

(8) Friction coefficient The resin film-forming film obtained in (6) was used. Using an automatic friction and wear analyzer (“TS-501” manufactured by Kyowa Interface Chemical Co., Ltd.), a vertical load of 50 g is applied to the line contact with respect to the resin film forming surface, and the moving speed is 2.5 mm / s in the horizontal direction. It was moved 8 mm and the friction force at 25 ° C. was measured. The friction coefficient was obtained by dividing the frictional force by the load.
In addition, the maximum friction coefficient immediately after the movement of the line contactor was defined as a static friction coefficient μs, and the average friction coefficient after the movement of the line contactor was defined as a dynamic friction coefficient μk.

(9) Adhesive strength The resin film-forming film obtained in (6) and the colored layer-forming film obtained in (7) were used. The film surface of the resin film-forming film and the colored layer of the colored layer-forming film are overlapped so that they are in close contact with each other and bonded together under the conditions of upper and lower roll surface temperature of 80 ° C., linear pressure of 40 N / cm, and speed of 1 m / min. For 72 hours to obtain a laminate.
The laminate was cut into strips with a width of 15 mm, and a 90 ° peel test was performed at 20 ° C. and a peel rate of 50 mm / min. In the measurement, N = 3, and the average value was defined as the adhesive strength. Practically, it is preferably 6 N / cm or more.

(10) Heat resistance Adhesive strength was measured in the same manner as the method for measuring adhesive strength in (9) except that a 90-degree peel test was performed at 50 ° C. Most preferably, it is equivalent to the adhesive strength of (9), and even when the strength is lower than the adhesive strength of (9), it is preferably 4 N / cm or more.

Production Example 1
20 mol% of terephthalic acid, 30 mol% of isophthalic acid, 15 mol% of azelaic acid, 35 mol% of ε-caprolactone, 63 mol% of 1,4-butanediol, 2 mol of ethylene oxide 2 mol adduct of bisphenol A (molecular weight about 1000) The raw material was put in an esterification reaction can so as to be%, and esterification was carried out at 220 ° C. for 5 hours under a pressure of 0.25 MPa while stirring at a rotation speed of 100 rpm with an anchor blade stirrer. Then, it is transferred to a polycondensation can, charged with a polymerization catalyst, gradually depressurized to 1.3 hPa over 60 minutes, and subjected to a polycondensation reaction at 240 ° C. until a predetermined molecular weight is reached. Resin (a1) was obtained. The number average molecular weight of the obtained polyester resin (a1) was 22000, Tg was −25 ° C., the acid value was 2.0 mgKOH / g, and the hydroxyl value was 4.0 mgKOH / g.

In addition, the abbreviation in Table 1 and Table 2 mentioned later shows the following, respectively.
TPA: terephthalic acid IPA: isophthalic acid AD: adipic acid AZ: azelaic acid SE: sebacic acid ECL: ε-caprolactone PHBA: 4-hydroxybenzoic acid GHB: 4-hydroxybutyric acid BD: 1,4-butanediol EG: ethylene glycol NPG: neopentyl glycol MPD: 2-methyl-1,3-propanediol HD: 1,6-hexanediol BAEO: 10 mol of bisphenol A ethylene oxide adduct (molecular weight about 1000)
PTMG: Polytetramethylene glycol (molecular weight: 1000)

Production Examples 2-32
Except having carried out like Table 1 and Table 2, it carried out similarly to manufacture example 1, and obtained polyester resin (a2)-(a22), (b1)-(b10). Further, the same operation as (a11) is performed, a polyester resin (a11 *) having a number average molecular weight of 26000, a polyester resin (a11 **) having a number average molecular weight of 31000, and a polyester resin having a number average molecular weight of 3700. (A11 ***) was also obtained. The polyester resins (a11 *) to (a11 ***) were all the same as the polyester resin (a11) except for the number average molecular weight and the hydroxyl value. The hydroxyl value changes with the number average molecular weight.
The results are shown in Table 1 or 2.

Example 1
The polyester resin (a11) obtained in Production Example 1 was charged with a mixed solvent of toluene and methyl ethyl ketone in a mass ratio of 8: 2 so that the resin solids concentration was 20% by mass, sealed, and dissolved with a paint shaker. A solution was obtained. Each characteristic was evaluated using the obtained resin solution. The results are shown in Table 3.

In addition, the abbreviations in Table 3 and Table 4 described below indicate the following, respectively.
IPDI: isophorone diisocyanate MDI: diphenylmethane diisocyanate HDI: hexamethylene diisocyanate

Examples 2-9
Except having used the polyester resin of Table 3, the resin solution was obtained like Example 1 and each characteristic was evaluated. The results are shown in Table 3.

Examples 10-13
Except having used each hardening | curing agent with respect to the polyester resin of Table 3, the resin solution was obtained like Example 1 and each characteristic was evaluated. The results are shown in Table 3.

Examples 14-30, Comparative Examples 1-8
As shown in Tables 3 to 5, two kinds of polyester resins were mixed and used. Except having used each hardening | curing agent with respect to the mixed resin, the resin solution was obtained like Example 1 and each characteristic was evaluated. The results are shown in Tables 3-5.

  Since the resin film obtained in Examples 1 to 30 uses a predetermined polyester resin, the friction property and the adhesive strength are improved. In particular, in bonding with a colored layer forming film, the adhesive strength was high, and the decrease in adhesive strength was small even at high temperatures. Moreover, since the friction coefficient was in an appropriate range, the handleability during processing was good. Especially, in Examples 16-30, the tendency for adhesive strength to improve was high.

  By contrast with Examples 1-4, even if the composition of the used polyester resin was the same, the static friction coefficient (micro | micron | mu) s became small because the number average molecular weight became high. On the other hand, the difference (μs−μk) between the static friction coefficient μs and the dynamic friction coefficient μk tended to be small. All of these had the same adhesive strength and heat resistance.

  By comparing Examples 6, 10, 14, 15, and 16, the following was found. That is, even if the composition of the polyester resin is the same, the adhesive strength is improved by containing a curing agent, and the effect of isophorone diisocyanate is better than that of diphenylmethane diisocyanate as the curing agent. Moreover, even if it is a case where a coloring agent is contained with respect to a film component, it has practical adhesive strength. Furthermore, the polyester resin was used as a mixed resin rather than a single resin, and the improvement effect was higher with respect to the improvement in adhesiveness, particularly the decrease in the adhesive strength at high temperatures.

  In Comparative Example 1, since no oxycarboxylic acid was contained as a component constituting the polyester resin, the adhesive strength was lowered.

  In Comparative Example 2, since the content of isophthalic acid as the component constituting the polyester resin was less than the lower limit, the adhesive strength was lowered.

 In Comparative Example 3, since the content of isophthalic acid exceeded the upper limit as a component constituting the polyester resin, the heat resistance was lowered.

  In Comparative Example 4, since the content of the aliphatic dicarboxylic acid having 6 to 12 carbon atoms was less than the lower limit as a component constituting the polyester resin, the adhesive strength was lowered.

  In Comparative Example 5, because the content of the aliphatic dicarboxylic acid having 6 to 12 carbon atoms exceeded the upper limit as a component constituting the polyester resin, the heat resistance was lowered.

  In Comparative Example 6, since the hydroxyl value of the polyester resin exceeded the upper limit, the adhesive strength was lowered.

 In Comparative Example 7, since the hydroxyl value of the polyester resin was less than the lower limit, the heat resistance was lowered.

In Comparative Example 8, the heat resistance decreased because the content of the oxycarboxylic acid in the polyester resin exceeded the upper limit.

Claims (8)

  A polyester resin having a hydroxyl value of 3 to 30 mgKOH / g and a glass transition temperature of less than 40 ° C., and 10 to 70 mol% of isophthalic acid and 10 to 10 aliphatic dicarboxylic acid having 6 to 12 carbon atoms as an acid component constituting the polyester resin. Polyester resin containing 50 mol% and oxycarboxylic acid 5-30 mol%.   The polyester resin comprises a polyester resin (a) having a glass transition temperature of less than 0 ° C. and a polyester resin (b) having a glass transition temperature of 0 ° C. or more and less than 40 ° C., and (a) / (b) = 90/10 to 10 The polyester resin according to claim 1, which is / 90 (mass ratio).   A resin solution obtained by dissolving the polyester resin according to claim 1 or 2 in an organic solvent.   Furthermore, the resin solution of Claim 3 containing a hardening | curing agent.   The resin solution according to claim 4, wherein the curing agent is isophorone diisocyanate.    The film obtained from the resin solution in any one of Claims 3-5.   The laminated body laminated | stacked in order of (1st base material) / (colored layer) / (coat of Claim 6) / (2nd base material). The method for producing a laminate according to claim 7, wherein the first base material on which the colored layer is formed and the second base material on which the coating film according to claim 6 is formed are bonded together.