JP7047977B2 - Polyester, adhesives and films - Google Patents

Description

The present invention relates to polyesters, adhesives and films. More specifically, the present invention relates to polyester having excellent dielectric properties, and an adhesive and a film containing the polyester.

Polyester is widely used as a raw material for resin compositions used in coating agents, inks, adhesives and the like, and is generally composed of a polyvalent carboxylic acid and a polyhydric alcohol. It is widely used in various applications such as coating agents and adhesives because it can freely control the flexibility and high and low molecular weights by selecting and combining polyvalent carboxylic acids and polyhydric alcohols.

Among them, polyester has excellent adhesiveness to metals including copper, and has been used as an adhesive for flexible printed wiring boards (FPC) by blending a curing agent such as epoxy resin. (For example, Patent Document 1).

Since FPC has excellent flexibility, it can be used for multi-functionality and miniaturization of personal computers (PCs) and smartphones, and is therefore often used for incorporating electronic circuit boards into narrow and complicated interiors. There is. In recent years, the miniaturization, weight reduction, high density, and high output of electronic devices have progressed, and due to these trends, the demand for the performance of wiring boards (electronic circuit boards) has become more and more sophisticated. In particular, as the speed of transmission signals in FPCs increases, the frequency of signals is increasing. Along with this, there is an increasing demand for FPCs to have low dielectric properties (low dielectric constant, low dielectric loss tangent) in the high frequency region. As for the base material used for FPC, not only the conventional polyimide (PI) and polyethylene terephthalate (PET), but also the base film such as liquid crystal polymer (LCP) and syndiotactic polystyrene (SPS) having low dielectric properties. Has been proposed. In order to achieve such low dielectric properties, measures have been taken to reduce the dielectric loss of the base material of the FPC and the adhesive. As an adhesive, a combination of polyolefin and epoxy (Patent Document 2) and the like are being developed.

Special fair 6-104813 WO2016 / 047289A

However, the polyester resin described in Patent Document 1 has a high relative permittivity and dielectric loss tangent, does not have the above-mentioned low dielectric property, and is unsuitable for FPC in a high frequency region. Further, it cannot be said that the adhesive described in Patent Document 2 is excellent in heat resistance of the adhesive used for the reinforcing plate and the layers.

The present invention has been made in the background of the problems of the prior art. That is, an object of the present invention is to provide a polyester having excellent solvent solubility, heat resistance, tackiness, low relative permittivity and dielectric loss tangent, and excellent dielectric properties, and an adhesive containing the same.

As a result of diligent studies, the present inventors have found that the above problems can be solved by the means shown below, and have arrived at the present invention.
That is, the present invention has the following configuration.

It has a polyvalent carboxylic acid component and a polyhydric alcohol component as structural units, and when the polyvalent carboxylic acid component is 100 mol%, it contains 50 mol% or more of the naphthalenedicarboxylic acid component and 100 mol of the polyhydric alcohol component. %, A polyester containing 20 mol% or more of a dimerdiol component.

The polyester preferably has a glass transition temperature of −30 ° C. or higher.

A polyester having a relative permittivity (εc) of 3.0 or less and a dielectric loss tangent (tan δ) of 0.008 or less at 10 GHz.

An adhesive containing the polyester.

A film containing the polyester.

The polyester of the present invention has excellent solvent solubility, heat resistance, tackiness, and dielectric properties. Therefore, it is suitable as an adhesive and a film for FPC in a high frequency region.

Hereinafter, one embodiment of the present invention will be described in detail below. However, the present invention is not limited to this, and can be carried out in a mode in which various modifications are added within the range described above.

The polyester of the present invention has a chemical structure that can be obtained by a polycondensate of a polyvalent carboxylic acid component and a polyhydric alcohol component, and the polyvalent carboxylic acid component and the polyhydric alcohol component are one or more, respectively. It consists of selected components of.

The polyester of the present invention contains 50 mol% or more of the naphthalene dicarboxylic acid component out of 100 mol% of the total polyvalent carboxylic acid component. It is preferably 70 mol% or more, more preferably 80 mol% or more, particularly preferably 90 mol% or more, and 100 mol% may be used. The dielectric property of polyester is improved by using a large amount of naphthalene carboxylic acid component.

Examples of the naphthalenedicarboxylic acid component include 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid and the like. , Any of them can be used, and two or more kinds may be used. Of these, 2,6-naphthalenedicarboxylic acid is preferable because it is excellent in reactivity and availability during polymerization.

The polyester of the present invention can contain a polyvalent carboxylic acid component other than the naphthalene dicarboxylic acid component. The polyvalent carboxylic acid component other than the naphthalenedicarboxylic acid component is not particularly limited, but the polyvalent carboxylic acid component is preferably an aromatic polyvalent carboxylic acid component or an alicyclic polyvalent carboxylic acid component, and is aromatic. It is more preferably a group dicarboxylic acid component or an alicyclic group dicarboxylic acid component. By using an aromatic polyvalent carboxylic acid component or an alicyclic polyvalent carboxylic acid component as the copolymerization component, excellent dielectric properties can be exhibited.

The aromatic dicarboxylic acid component is not particularly limited, but terephthalic acid, isophthalic acid, orthophthalic acid, 4,4'-dicarboxybiphenyl, 5-sodium sulfoisophthalic acid, or an ester thereof can be used.

The alicyclic dicarboxylic acid component is not particularly limited, but is limited to 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, tetrahydrophthalic acid anhydride, and methyltetrahydrophthalic acid anhydride. A substance, a hydrogenated naphthalenedicarboxylic acid, or the like can be used.

The polyester of the present invention contains 20 mol% or more of dimerdiol in 100 mol% of the total polyhydric alcohol component. It is preferably 30 mol% or more, and more preferably 40 mol% or more. The use of a large amount of dimer diol improves the dielectric properties and solvent solubility of polyester.

The dimer diol can be obtained by reducing the carboxyl groups of a dimer acid having 20 to 48 carbon atoms obtained by dimerizing an unsaturated fatty acid of C10 to 24 and a saturated dimer acid obtained by hydrogenating them. .. Moreover, you may use vegetable oil as a raw material of dimerdiol. Further, the dimer diol may contain a trimer which is a trimer of an unsaturated fatty acid of C10 to 24 or a saturated trimmer obtained by hydrogenating the trimmer.

The polyester of the present invention can contain a polyhydric alcohol component other than dimerdiol. The polyhydric alcohol other than dimerdiol is not particularly limited, but is limited to ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, and 1,4-. Butanediol, 2-methyl-1,3-propanediol, neopentylglycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 2-Methyl-2-ethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-ethyl-2-n-propyl-1,3-propanediol, 2,2-di -N-propyl-1,3-propanediol, 2-n-butyl-2-ethyl-1,3-propanediol, 2,2-di-n-butyl-1,3-propanediol, 2,4- Aliper polyhydric alcohols such as diethyl-1,5-pentanediol and 2-ethyl-1,3-hexanediol, alicyclic polyvalent alcohols such as 1,4-cyclohexanedimethanol and tricyclodecanedimethanol, and poly. Polyalkylene ether glycols such as tetramethylene glycol and polypropylene glycol can be used, and one or more of these can be used. Of these, tricyclodecanedimethanol is preferable.

The polyester of the present invention can also be copolymerized with a trivalent or higher polyvalent carboxylic acid component and / or a trivalent or higher polyhydric alcohol component. Examples of the trivalent or higher valent carboxylic acid component include aromatic carboxylic acids such as trimellitic acid, pyromellitic acid, benzophenone tetracarboxylic acid, trimesic acid, trimellitic anhydride (TMA), and pyromellitic anhydride (PMDA). , 1, 2, 3, 4-Butanetetracarboxylic acid and other aliphatic carboxylic acids can be mentioned, and one or more of these can be used. Examples of the trihydric or higher polyhydric alcohol component include glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, α-methylglucose, mannitol, and sorbitol, and one or more of these may be used. It is possible. However, if the amount of copolymerization of the trivalent or higher polyvalent carboxylic acid component and / or the trivalent or higher polyhydric alcohol component is large, the dielectric properties of the polyester may deteriorate, which is not preferable. When copolymerizing a trivalent or higher polyvalent carboxylic acid component and / or a trivalent or higher polyhydric alcohol component, 5 mol% or less of the total of 200 mol% of the polyvalent carboxylic acid component and the polyhydric alcohol component is preferable. , More preferably 4 mol% or less.

The dielectric loss tangent of the polyester of the present invention at 10 GHz is preferably 0.008 or less, more preferably 0.005 or less. By using a polyester having a low dielectric loss tangent, it is possible to form an adhesive composition having good low dielectric properties.

The relative permittivity of the polyester of the present invention at 10 GHz is preferably 3.0 or less, more preferably 2.6 or less. By using a polyester having a low relative permittivity, it is possible to form an adhesive composition having good low dielectric properties.

The glass transition temperature of the polyester of the present invention is preferably −30 ° C. or higher, more preferably −20 ° C. or higher. By setting the glass transition temperature in the range of −30 ° C. or higher, good dielectric properties are exhibited. Further, the tackiness (adhesiveness) of the resin surface tends to be suppressed, and the handleability of the resin is improved. Further, the glass transition temperature is preferably 100 ° C. or lower. By setting the glass transition temperature to 100 ° C. or lower, laminating can be performed even at a low temperature of about 80 ° C. Further, the lower the glass transition temperature, the better the adhesive strength tends to be.

As a method of the polymerization condensation reaction for producing the polyester of the present invention, for example, 1) a polyhydric carboxylic acid and a polyhydric alcohol are heated in the presence of a known catalyst, subjected to a dehydration esterification step, and then depolyhydric alcohol / heavy. Method of performing condensation reaction 2) Method of heating alcohol ester of polyvalent carboxylic acid and polyhydric alcohol in the presence of a known catalyst, and performing transesterification reaction to depolyhydric alcohol / polycondensation reaction 3) Solution There is a method of performing polymerization. In the methods 1) and 2) above, part or all of the acid component may be replaced with acid anhydride.

In producing the polyester of the present invention, conventionally known polymerization catalysts such as titanium compounds such as tetra-n-butyl titanate, tetraisopropyl titanate and titaniumoxyacetylsetonate, antimony trioxide and antimony such as tributoxyantimony are produced. Compounds, germanium compounds such as germanium oxide and tetra-n-butoxygermanium, and acetates such as magnesium, iron, zinc, manganese, cobalt, and aluminum can be used. These catalysts may be used alone or in combination of two or more.

The number average molecular weight of the polyester of the present invention is preferably 5000 or more, and more preferably 10,000 or more. Further, it is preferably 100,000 or less, more preferably 50,000 or less, and further preferably 30,000 or less. Within the above range, it is preferable because it is easy to handle when dissolved in a solvent, the adhesive strength is good, and the dielectric property is excellent.

The acid value of the polyester of the present invention is preferably 200 eq / 10 ⁶ g or less, more preferably 100 eq / 10 ⁶ g or less, still more preferably 50 eq / 10 ⁶ g or less, and 40 eq / 10. It is particularly preferably ⁶ g or less, and most preferably 30 eq / 10 ⁶ g or less. By keeping the resin acid value within the above range, low dielectric properties and pot life are excellent, and in the isocyanate curing system, the effect of improving the adhesion to the substrate and the crosslinkability can be expected.

As a method for increasing the acid value of the polyester of the present invention, for example, (1) after completion of the polycondensation reaction, a trivalent or higher polyvalent carboxylic acid and / or a trivalent or higher anhydrous polyvalent carboxylic acid is added and reacted. There are methods (acid addition) and (2) heat, oxygen, water and the like to act on the polycondensation reaction to intentionally alter the resin, and these can be performed arbitrarily. The polyvalent carboxylic acid anhydride used for acid addition in the acid addition method is not particularly limited, but for example, trimellitic anhydride, pyromellitic anhydride, hexahydrophthalic anhydride, 3,3', 4, Examples thereof include 4'-benzophenone tetracarboxylic acid dianhydride, 3,3,4,4-biphenyltetracarboxylic acid dianhydride, ethylene glycol bisanhydrotrimeritate, and one or more of these. It can be used. It is preferably trimellitic anhydride.

The polyester of the present invention can be used as an adhesive. In particular, since the polyester of the present invention has excellent dielectric properties, it is suitable as an adhesive for FPC in a high frequency region.
When the polyester of the present invention is used as an adhesive, it can further contain a curing agent to form an adhesive composition. As the curing agent, an epoxy resin, polyisocyanate, polycarbodiimide or the like can be used. By cross-linking with these curing agents, the cohesive force of the resin can be increased and the heat resistance can be improved. Polyisocyanate is preferable because it has little effect on heat resistance and dielectric properties. The content of the curing agent is preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, still more preferably 1 part by mass or more, and particularly preferably 1 part by mass or more with respect to 100 parts by mass of polyester. It is preferably 2 parts by mass or more. By setting the value to the lower limit or more, a sufficient curing effect can be obtained, and excellent adhesiveness and solder heat resistance can be exhibited. Further, it is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, further preferably 15 parts by mass or less, and particularly preferably 10 parts by mass or less. By setting the value to the upper limit or less, the pot life property and the low dielectric property are improved. That is, within the above range, an adhesive composition having excellent low dielectric properties in addition to adhesiveness, solder heat resistance and pot life property can be obtained.

The polyester of the present invention can be used as a film. When the polyester of the present invention is used as a film, the polyester may be processed into a film as it is, or a film in which various fillers such as glass fiber and silica are dispersed may be processed into a film. You can also. The thickness and shape of the film of the present invention are not particularly limited, and include a form often referred to as a sheet.
Since the film of the present invention has excellent dielectric properties, it is suitable as a rigid substrate for high-speed transmission or a CCL base film for FPC.

Hereinafter, the present invention will be specifically described with reference to examples. In addition, in this Example and a comparative example, a simple part means a mass part.

( ¹ ) Measurement of polyester composition Using a 400 MHz 1H-nuclear magnetic resonance spectrum device (hereinafter, may be abbreviated as NMR), the molar ratio of the polyvalent carboxylic acid component and the polyvalent alcohol component constituting the polyester is quantified. Was done. Deuterated chloroform was used as the solvent. When the acid value of the polyester was increased by the post-acid addition, the molar ratio of each component was calculated with the total of the acid components other than the acid components used for the post-acid addition as 100 mol%.

(2) Measurement of glass transition temperature Measurement was performed using a differential scanning calorimeter (SII, DSC-200). 5 mg of the sample (polyester) was placed in an aluminum holding lid type container, sealed, and cooled to −50 ° C. using liquid nitrogen. Next, the temperature is raised to 150 ° C. at a heating rate of 20 ° C./min, and in the heat absorption curve obtained in the temperature rise process, an extension of the baseline before the heat absorption peak appears (below the glass transition temperature) and the heat absorption peak. The glass transition temperature (Tg, unit: ° C.) was defined as the temperature of the intersection with the tangent line toward the peak (the tangent line indicating the maximum slope from the rising portion of the peak to the peak of the peak).

(3) Measurement of number average molecular weight A polyester sample is dissolved and / or diluted with tetrahydrofuran so that the resin concentration is about 0.5% by weight, and filtered through a polytetrafluoride ethylene membrane filter having a pore size of 0.5 μm. Was used as a measurement sample. The molecular weight was measured by gel permeation chromatography (GPC) using tetrahydrofuran as a mobile phase and a differential refractometer as a detector. The flow rate was 1 mL / min and the column temperature was 30 ° C. Showa Denko's KF-802, 804L, and 806L were used as columns. Monodisperse polystyrene was used as the molecular weight standard.

(4) Measurement of acid value 0.2 g of a polyester sample is dissolved in 40 ml of chloroform and titrated with 0.01 N potassium hydroxide ethanol solution to determine the equivalent (eq / 10 ⁶ g) per ¹⁰⁶ g of polyester. rice field. Phenolphthalein was used as an indicator.

Hereinafter, a production example of the polyester of the present invention and a polyester as a comparative example will be shown.

(Example 1)
Production example of polyester (a1) 326 parts of dimethyl 2,6-naphthalenedicarboxylate, 1520 parts of dimerdiol (Croda, Pripol 2033) in a reaction vessel equipped with a stirrer, condenser, and thermometer, and total acid tetrabutyl orthotitanium as a catalyst. 0.03 mol% of the component was charged, the temperature was raised from 160 ° C. to 220 ° C. over 4 hours, and the esterification reaction was carried out through a dehydration step. Next, in the polycondensation reaction step, the pressure inside the system was reduced to 5 mmHg over 20 minutes, and the temperature was further raised to 250 ° C. Then, the pressure was reduced to 0.3 mmHg or less, a polycondensation reaction was carried out for 60 minutes, and then this was taken out. As a result of composition analysis by NMR, the obtained polyester (a1) had a molar ratio of 2,6-naphthalenedicarboxylic acid / dimerdiol = 100/100 [molar ratio]. The glass transition temperature was -17 ° C. The obtained polyester (a1) was evaluated for solvent solubility, tackiness, heat resistance, relative permittivity and dielectric loss tangent. The evaluation results are shown in Table 1.

(Examples 2 to 8, Comparative Examples 1 to 7)
Production Examples of Polyesters (a2) to (a14) Polyesters (a2) to (a14) were synthesized by changing the types of raw materials and the blending ratio according to the production examples of polyester (a1). The physical characteristics and evaluation results are shown in Table 1. PTMG1000 is polytetramethylene ether glycol (average molecular weight 1000).

Relative permittivity (ε _c ) and dielectric loss tangent (tan δ)
Polyester dissolved in toluene so as to have a solid content concentration of 30% by mass was applied to a Teflon (registered trademark) sheet having a thickness of 100 μm so as to have a thickness of 25 μm after drying, and dried at 130 ° C. for 3 minutes. Then, the Teflon (registered trademark) sheet was peeled off to obtain a resin sheet for testing. After that, the obtained test resin sheet was cut into strips of 8 cm × 3 mm to obtain a test sample. The relative permittivity (ε _c ) and the dielectric loss tangent (tan δ) were measured by a cavity resonator perturbation method using a network analyzer (manufactured by Anritsu) under the conditions of a temperature of 23 ° C. and a frequency of 10 GHz.
<Relative permittivity evaluation criteria>
⊚: 2.3 or less ○: More than 2.3, 3.0 or less ×: More than 3.0 <Evaluation criteria for dielectric loss tangent>
⊚: 0.005 or less ○: More than 0.005, 0.008 or less ×: More than 0.008

A polyester varnish dissolved in tacky toluene so that the solid content concentration is 30% by mass is applied to a polyester film (Toyobo E5101, thickness 50 μm, corona-treated surface) so that the thickness after drying is 25 μm, and 130 It was dried at ° C for 3 minutes. At room temperature (23 ° C), the dried adhesive sheet is cut to a width of 25 mm and a length of 200 mm, and the adhesive layer surface is attached to a rolled copper foil base material (JX Metal Co., Ltd., BHY series), and 2 kg from the top. The adhesive sheet was crimped by reciprocating twice at a speed of 20 mm / sec with the rubber roller of. Then, the peeling was performed by 180 ° under the condition of a peeling speed of 300 mm / min, and the state of the peeled base material was confirmed. The case where the base material had no adhesive residue and the interface was peeled off was marked with ◯, and the case where the adhesive layer was transferred to the base material side was marked with x.
<Evaluation criteria for tackiness>
◯: Interface peeling without adhesive residue ×: Adhesive residue is present or the adhesive layer is transferred to the substrate side

Solvent Solubility The solubility of polyester dissolved in toluene with stirring at 80 ° C. for 6 hours so that the solid content concentration was 60% by mass or 50% by mass was evaluated according to the following criteria.
<Evaluation criteria for solvent solubility>
⊚: Completely dissolved without remaining undissolved at a solid content concentration of 60% by mass ○: Completely dissolved without remaining undissolved at a solid content concentration of 50% by mass ×: Undissolved resin at a solid content concentration of 50% by mass

Heat resistance Measured using a differential thermal / thermogravimetric simultaneous measuring device (Shimadzu Corporation, DTG-60). 50 mg of polyester was placed in a platinum cell, and the temperature was raised to 1000 ° C. at a heating rate of 5 ° C./min under a nitrogen atmosphere at a flow rate of 20 ml / min. The temperature at which decomposition proceeded at a high temperature and the weight reached 95% of the initial weight was defined as the 5% weight loss temperature, which was used as an index of heat resistance.
<Evaluation criteria for heat resistance>
◯: 5% weight loss temperature is 300 ° C or higher ×: 5% weight loss temperature is less than 300 ° C

The polyester of the present invention is excellent in solvent solubility, heat resistance and tackiness, has a low relative permittivity and dielectric loss tangent, and is useful as an adhesive and a film for FPC in a high frequency region.

Claims (3)

It has a polyvalent carboxylic acid component and a polyhydric alcohol component as structural units, and when the polyvalent carboxylic acid component is 100 mol%, it contains 90 mol% or more of the naphthalenedicarboxylic acid component and 100 mol of the polyhydric alcohol component. %, An adhesive for a flexible printed wiring board containing polyester containing 30 mol% or more of a dimerdiol component. The adhesive for a flexible printed wiring board according to claim 1, wherein the polyester has a glass transition temperature of −30 ° C. or higher. The adhesive for a flexible printed wiring board according to claim 1 or 2, wherein the polyester has a relative permittivity (εc) of 3.0 or less and a dielectric loss tangent (tan δ) of 0.008 or less at 10 GHz.