KR20220161319A - Polyester, adhesives and films - Google Patents

Abstract

An object of the present invention is to provide polyester, which is excellent in solvent solubility, heat resistance, tackiness, low in dielectric constant and dielectric loss tangent, and excellent in dielectric properties, and an adhesive and a film containing the same.
It has a polyhydric carboxylic acid component and a polyhydric alcohol component as structural units, and when the polyhydric carboxylic acid component is 100 mol%, the naphthalenedicarboxylic acid component is contained at 50 mol% or more, and the polyhydric alcohol component is 100 mol%. Co-polyester containing 20 mol% or more of a dimerdiol component when used.

Description

Polyester, adhesives and films

The present invention relates to polyesters, adhesives and films. More specifically, it relates to polyesters having excellent dielectric properties, and adhesives and films containing the same.

Polyester is widely used as a raw material for resin compositions used in coating agents, inks and adhesives, and is generally composed of polyhydric carboxylic acids and polyhydric alcohols. Since flexibility and molecular weight can be freely controlled by selecting and combining polyhydric carboxylic acids and polyhydric alcohols, they are widely used in various applications including coating agent applications and adhesive applications.

Among them, polyester is excellent in adhesion to metals including copper, and has been used in adhesives such as flexible printed wiring boards (FPC) by blending curing agents such as epoxy resins. (eg Patent Document 1).

Since FPCs have excellent flexibility, they can respond to multifunctionality and miniaturization of personal computers (PCs) and smart phones, and for this reason, they are widely used to insert electronic circuit boards into narrow and complicated interiors. In recent years, miniaturization, weight reduction, high density, and high output of electronic devices are progressing, and due to this trend, the demand for the performance of a wiring board (electronic circuit board) is becoming more and more sophisticated. In particular, with the high-speed transmission signal in the FPC, the high-frequency signal is progressing. Accordingly, demand for low dielectric properties (low dielectric constant, low dielectric loss tangent) in the high frequency region is increasing for FPCs. In addition, regarding the base material used for FPC, not only conventional polyimide (PI) and polyethylene terephthalate (PET), but also base films such as liquid crystal polymer (LCP) and syndiotactic polystyrene (SPS) having low dielectric properties are used. It is proposed. In order to achieve such a low dielectric property, measures are taken to reduce dielectric loss of FPC substrates and adhesives. As an adhesive, development of a combination of polyolefin and epoxy (Patent Document 2) and the like is in progress.

Patent Document 1: Japanese Patent Publication Hei 6-104813 Patent Document 2: WO2016/047289 Publication

However, the polyester resin described in Patent Literature 1 has a high relative permittivity and a high dielectric loss tangent, and does not have the above-described low dielectric properties, making it unsuitable for FPCs in the high frequency region. In addition, it is difficult to say that the adhesive disclosed in Patent Literature 2 is excellent in heat resistance of an adhesive used between a reinforcing plate or between layers.

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

MEANS TO SOLVE THE PROBLEM The present inventors discovered that the said subject was solvable by the means shown below, as a result of earnest examination, and reached this invention.

That is, the present invention consists of the following configurations.

It has a polyhydric carboxylic acid component and a polyhydric alcohol component as structural units, and when the polyhydric carboxylic acid component is 100 mol%, the naphthalenedicarboxylic acid component is contained at 50 mol% or more, and the polyhydric alcohol component is 100 mol%. Polyester containing 20 mol% or more of a dimerdiol component.

It is preferable that the said polyester has a glass transition temperature of -30 degreeC or more.

Polyester having a dielectric constant (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 is excellent in solvent solubility, heat resistance and tackiness, and also excellent in dielectric properties. For this reason, it is suitable as an adhesive and film for FPCs in the 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 implemented in an aspect in which various modifications are added within the range already described.

The polyester of the present invention has a chemical structure obtained by a polycondensate of a polyhydric carboxylic acid component and a polyhydric alcohol component, and the polyhydric carboxylic acid component and polyhydric alcohol component are each composed of one or two or more selected components. it is done

Polyester of this invention contains 50 mol% or more of naphthalenedicarboxylic acid components in 100 mol% of all polyhydric carboxylic acid components. Preferably it is 70 mol% or more, more preferably 80 mol% or more, particularly preferably 90 mol% or more, and even 100 mol% is not a problem. Dielectric properties of polyester are improved by using a large amount of naphthalenedicarboxylic acid component.

As the naphthalenedicarboxylic acid component, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 1 ,8-naphthalenedicarboxylic acid etc. are mentioned, All can be used, You may use 2 or more types. Among them, 2,6-naphthalenedicarboxylic acid is preferable because of its excellent reactivity and availability during polymerization.

The polyester of the present invention may contain a polyhydric carboxylic acid component other than the naphthalenedicarboxylic acid component. The polyvalent carboxylic acid component other than the naphthalene dicarboxylic acid component is not particularly limited, but the polyhydric carboxylic acid component is preferably an aromatic polycarboxylic acid component or an alicyclic polyvalent carboxylic acid component, and an aromatic dicarboxylic acid component is preferred. It is more preferable that it is a carboxylic acid component or an alicyclic dicarboxylic acid component. Excellent dielectric properties can be expressed by using an aromatic polyhydric carboxylic acid component or an alicyclic polyhydric carboxylic acid component as a copolymerization component.

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

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

The polyester of the present invention contains 20 mol% or more of dimerdiol based on 100 mol% of all polyhydric alcohol components. Preferably it is 30 mol% or more, More preferably, it is 40 mol% or more. By using a large amount of dimerdiol, the dielectric properties and solvent solubility of polyester are improved.

The dimer diol is obtained by reducing the carboxyl group of dimer acids having 20 to 48 carbon atoms obtained by dimerizing C10 to 24 unsaturated fatty acids and saturated dimer acids obtained by hydrogenating them. Moreover, you may use vegetable oil as a raw material of dimer diol. The dimer diol may further contain a trimer which is a trimer of C10-24 unsaturated fatty acids or a saturated trimer obtained by hydrogenating the trimer.

The polyester of the present invention may contain polyhydric alcohol components other than dimer diol. Polyhydric alcohols other than dimerdiol are not particularly limited, but ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 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-diethyl- Aliphatic polyhydric alcohols such as 1,5-pentanediol and 2-ethyl-1,3-hexanediol; alicyclic polyhydric alcohols such as 1,4-cyclohexanedimethanol and tricyclodecane dimethanol; polytetramethylene glycol; Polyalkylene ether glycol, such as propylene glycol, etc. can be used, One type or two or more types can be used among these. Especially, tricyclodecane dimethanol is preferable.

A trivalent or higher polyhydric carboxylic acid component and/or a trivalent or higher polyhydric alcohol component may be copolymerized with the polyester of the present invention. Examples of the trivalent or higher polyhydric carboxylic acid component include aromatic carboxylic acids such as trimellitic acid, pyromellitic acid, benzophenonetetracarboxylic acid, trimesic acid, trimellitic anhydride (TMA), and pyromellitic anhydride (PMDA). aliphatic carboxylic acids such as boxylic acid and 1,2,3,4-butanetetracarboxylic acid; and the like, and these can be used alone or in combination of two or more. Examples of the trihydric or higher polyhydric alcohol component include glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, α-methylglucose, mannitol, and sorbitol, and one or two or more of these can be used. . However, when the copolymerization amount of the trivalent or higher polyhydric carboxylic acid component and/or the trivalent or higher polyhydric alcohol component is large, the dielectric properties of polyester may be deteriorated, which is not preferable. When copolymerizing a trivalent or higher polyhydric carboxylic acid component and/or a trivalent or higher polyhydric alcohol component, the amount is preferably 5 mol% or less out of 200 mol% in total of the polyhydric carboxylic acid component and the polyhydric alcohol component, 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 being polyester with a low dielectric loss tangent, an adhesive composition with good low dielectric properties can be formed.

The relative permittivity at 10 GHz of the polyester of the present invention is preferably 3.0 or less, and more preferably 2.6 or less. By being polyester with a low dielectric constant, an adhesive composition with favorable low dielectric properties can be formed.

The glass transition temperature of the polyester of the present invention is preferably -30°C or higher, more preferably -20°C or higher. Favorable dielectric properties are expressed by setting the glass transition temperature in the range of -30°C or higher. Also, tackiness (stickiness) of the resin surface tends to be suppressed, and the handleability of the resin is improved. Moreover, it is preferable that the glass transition temperature is 100 degrees C or less. By setting the glass transition temperature to 100°C or less, lamination 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 polymerization condensation reaction method for producing the polyester of the present invention, for example, 1) a polyhydric alcohol/polycondensation reaction by heating a polyhydric carboxylic acid and a polyhydric alcohol in the presence of a known catalyst, passing through a dehydration esterification step, 2) a method in which an alcohol ester of a polyhydric carboxylic acid and a polyhydric alcohol are heated in the presence of a known catalyst and subjected to a transesterification reaction to conduct a dehydric alcohol/polycondensation reaction; 3) a method in which depolymerization is performed. . In the methods 1) and 2) above, part or all of the acid component may be substituted with an acid anhydride.

When producing the polyester of the present invention, conventionally known polymerization catalysts such as titanium compounds such as tetra-n-butyl titanate, tetraisopropyl titanate and titaniumoxyacetylcetonate, antimony trioxide, tributoxyantimony, etc. antimony compounds, germanium compounds such as germanium oxide and tetra-n-butoxy germanium, and acetate salts such as magnesium, iron, zinc, manganese, cobalt, and aluminum. These catalysts can use 1 type or 2 or more types together.

It is preferable that it is 5000 or more, and, as for the number average molecular weight of polyester of this invention, it is more preferable that it is 10000 or more. Moreover, it is preferable that it is 100000 or less, it is more preferable that it is 50000 or less, and it is still more preferable that it is 30000 or less. If it is within the above range, handling when dissolved in a solvent is easy, adhesive strength is improved, and dielectric properties are excellent, so it is preferable.

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 ⁶ g or less. It is particularly preferably less than or equal to 30 eq/10 6 g or less, and most preferably less than or equal to 30 eq/10 ⁶ g. By setting the acid value of the resin within the above range, the low dielectric properties and pot life are excellent, and in the case of an isocyanate-cured system, an effect of increasing adhesion to a substrate and crosslinking properties can also be expected.

As a method of raising the acid value of the polyester of the present invention, for example, (1) a method of reacting by adding a trivalent or higher polyhydric carboxylic acid and/or a trivalent or higher polyhydric carboxylic acid after completion of the polycondensation reaction (acid part) There are methods such as a) or (2) intentionally changing the quality of the resin by applying heat, oxygen, water, etc. during the polycondensation reaction, and these can be arbitrarily performed. The polyhydric carboxylic acid anhydride used for acid addition in the above acid addition method is not particularly limited, but examples include trimellitic anhydride, pyromellitic anhydride, hexahydrophthalic anhydride, 3,3',4,4' -benzophenonetetracarboxylic dianhydride, 3,3,4,4-biphenyltetracarboxylic dianhydride, ethylene glycol bisanhydrotrimellitate, etc., and the use of one or two or more of these It is possible. Preferred is 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 for FPC adhesives in the high frequency region.

When the polyester of the present invention is used as an adhesive, an adhesive composition may further contain a curing agent. As the curing agent, an epoxy resin, polyisocyanate, polycarbodiimide or the like can be used. By crosslinking with these curing agents, the cohesive force of the resin can be increased and the heat resistance can be improved. Polyisocyanate is preferable from the viewpoint of having little effect on heat resistance and dielectric properties. The content of the curing agent is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, still more preferably 1 part by mass or more, and particularly preferably 2 parts by mass or more with respect to 100 parts by mass of polyester. . Sufficient curing effect is obtained by setting it as more than the said lower limit, and excellent adhesiveness and solder|pewter heat resistance can be expressed. Further, it is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, still more preferably 15 parts by mass or less, and particularly preferably 10 parts by mass or less. By carrying out below the said upper limit, pot life property and a low dielectric characteristic become favorable. That is, by setting it within the above range, an adhesive composition having excellent low dielectric properties in addition to adhesiveness, solder heat resistance and pot life 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 form as it is and used, or a material in which various fillers such as glass fibers and silica are dispersed may be processed into a film form and used. The thickness or shape of the film of the present invention is not particularly limited, and a form often referred to as a sheet is also included here.

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.

Example

Hereinafter, the present invention will be described in detail by way of examples. On the other hand, in this Example and Comparative Example, "part" simply indicates a mass part.

(1) Measurement of composition of polyester

Using a 400 MHz ¹ H nuclear magnetic resonance spectrometer (hereinafter sometimes abbreviated as NMR), the molar ratio of the polyhydric carboxylic acid component and polyhydric alcohol component constituting the polyester was quantified. Deuterated chloroform was used as the solvent. On the other hand, when the acid value of the polyester was raised by post-acid addition, the molar ratio of each component was calculated by taking the total of acid components other than the acid component used for post-acid addition as 100 mol%.

(2) measurement of glass transition temperature

It was measured using a differential scanning calorimeter (SII, DSC-200). 5 mg of the sample (polyester) was placed in an aluminum press-lid container, sealed, and cooled to -50°C using liquid nitrogen. Subsequently, the temperature was raised to 150 ° C. at a temperature increase rate of 20 ° C./min, and in the endothermic curve obtained during the temperature increase process, the extension line of the baseline before the endothermic peak appeared (below the glass transition temperature) and the tangent line toward the endothermic peak (peak The temperature at the intersection of the tangential line representing the maximum slope between the rising portion of and the peak of the peak) was taken as the glass transition temperature (Tg, unit: ° C).

(3) Measurement of number average molecular weight

A polyester sample was dissolved and/or diluted with tetrahydrofuran to a resin concentration of about 0.5% by weight, and filtered through a polytetrafluoroethylene membrane filter with a pore diameter of 0.5 µm to obtain a sample for measurement. Molecular weight was measured by gel permeation chromatography (GPC) using tetrahydrofuran as a mobile phase and using a differential refractometer as a detector. The flow rate was 1 mL/min, and the column temperature was 30°C. KF-802, 804L, and 806L manufactured by Showa Denko were used for the column. Monodisperse polystyrene was used for molecular weight standards.

(4) measurement of acid value

A polyester sample of 0.2 g was dissolved in 40 ml of chloroform and titrated with a 0.01 N potassium hydroxide ethanol solution to obtain an equivalent weight per 10 ⁶ g of polyester (eq/10 ⁶ g). Phenolphthalein was used as the indicator.

Hereinafter, the polyester of this invention and the manufacturing example of the polyester used as a comparative example are shown.

(Example 1)

Production example of polyester (a1)

In a reaction vessel equipped with a stirrer, condenser, and thermometer, 326 parts of 2,6-naphthalenedicarboxylic acid dimethyl, 1520 parts of dimer diol (Croda, Pripol 2033), and tetrabutyl orthotitanate as a catalyst were added at 0.03 mol% based on the total acid components. Then, an esterification reaction was performed while passing through a temperature rising and dehydration process from 160°C to 220°C over 4 hours. 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, after reducing the pressure to 0.3 mmHg or less and performing a polycondensation reaction for 60 minutes, this was taken out. As a result of compositional analysis by NMR, the obtained polyester (a1) was 2,6-naphthalenedicarboxylic acid/dimerdiol = 100/100 [molar ratio] in terms of molar ratio. Moreover, the glass transition temperature was -17 degreeC. Regarding the obtained polyester (a1), each evaluation of solvent solubility, tackiness, heat resistance, dielectric constant, and dielectric loss tangent was performed. 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 according to the production example of polyester (a1) by changing the type of raw materials and the blending ratio. Physical properties and evaluation results are listed in Table 1. On the other hand, PTMG1000 is polytetramethylene ether glycol (average molecular weight 1000).

Relative permittivity (ε _c ) and dielectric loss tangent (tanδ)

Polyester dissolved in toluene at a solid concentration of 30% by mass was applied to a Teflon (registered trademark) sheet having a thickness of 100 μm to a thickness after drying of 25 μm, and dried at 130° C. for 3 minutes. Subsequently, the Teflon (registered trademark) sheet was peeled off to obtain a resin sheet for testing. Thereafter, samples were cut into strips of 8 cm x 3 mm from the obtained resin sheet for testing to obtain samples for testing. The dielectric constant (ε _c ) and the dielectric loss tangent (tan δ) were measured using a network analyzer (manufactured by Anritz Corporation) by a cavity resonator perturbation method under conditions of a temperature of 23°C and a frequency of 10 GHz.

<Evaluation Criteria for Relative Permittivity>

◎ : 2.3 or less

○: more than 2.3 and less than 3.0

×: greater than 3.0

<Evaluation Criteria for Dielectric Loss Tangent>

◎ : 0.005 or less

○: more than 0.005 and less than 0.008

×: greater than 0.008

tackiness

A polyester varnish dissolved in toluene at a solid content concentration of 30% by mass was applied to a polyester film (E5101 manufactured by Toyobo, thickness 50 μm, corona treated surface) to a thickness of 25 μm after drying, and held at 130 ° C. for 3 minutes It was dry. At room temperature (23°C), the dried adhesive sheet was cut into 25 mm in width and 200 mm in length, and the adhesive layer surface was adhered to a rolled copper foil base material (BHY series manufactured by JX Metal Co., Ltd.), and 20 mm from the top with a 2 kg rubber roller. The adhesive sheet was compressed by reciprocating twice at a speed of mm/sec. Then, it peeled 180 degrees under the conditions of the peeling speed of 300 mm/min, and the state of the peeled base material was confirmed. What was subjected to interfacial separation so that glue did not remain on the base material was rated as ○, and what the adhesive layer was transferred to the base material side was rated as ×.

<Evaluation Criteria for Tackiness>

○: Interface peeling so that no glue remains

×: Glue remains or the adhesive layer is transferred to the base material side

solvent solubility

The solubility when the polyester was dissolved in toluene with stirring at 80°C for 6 hours so as to have a solid content concentration of 60% by mass or 50% by mass was evaluated according to the following criteria.

<Evaluation Criteria for Solvent Solubility>

◎: Completely dissolved without dissolution residue at a solid content concentration of 60% by mass

○: Completely dissolved without dissolution residue at a solid content concentration of 50% by mass

×: There is a resin dissolution residue at a solid content concentration of 50% by mass

heat resistance

It was 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 at high temperature progresses and the weight becomes 95% of the initial value was set as the 5% weight loss temperature, and was used as an index of heat resistance.

<Evaluation criteria for heat resistance>

○: 5% weight loss temperature is 300 ℃ or more

×: 5% weight loss temperature is less than 300°C

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

Claims (5)

It has a polyhydric carboxylic acid component and a polyhydric alcohol component as structural units, and when the polyhydric carboxylic acid component is 100 mol%, the naphthalenedicarboxylic acid component is contained at 50 mol% or more, and the polyhydric alcohol component is 100 mol%. Polyester containing 20 mol% or more of a dimerdiol component. The polyester according to claim 1, having a glass transition temperature of -30°C or higher. The polyester according to claim 1 or 2, wherein the relative permittivity (εc) at 10 GHz is 3.0 or less and the dielectric loss tangent (tan δ) is 0.008 or less. An adhesive containing the polyester according to any one of claims 1 to 3. A film containing the polyester according to any one of claims 1 to 3.