JP7443757B2 - Insulating member for batteries made of polyphenylene sulfide resin composition - Google Patents

Description

The present invention relates to a battery insulating member made of a polyphenylene sulfide resin composition that has excellent toughness, electrolyte resistance, heat resistance, and moldability.

The battery is provided with an insulating member for the purpose of preventing an internal short circuit between a pair of terminals. In conventional insulating members, polyolefin resins such as polyethylene resins and polypropylene resins, which have electrolyte resistance and toughness, have been used to maintain insulation and ensure safety during actual use.

In recent years, with the miniaturization of electronic devices and the spread of electric vehicles, the capacity and energy density of secondary batteries in particular have been increasing. Therefore, in secondary batteries, the insulating member is exposed to higher temperatures when an abnormality occurs, and the insulating member is also required to have heat resistance. Against this background, there is a need to create a new resin material that has toughness, electrolyte resistance, heat resistance, etc. in place of polyolefin resins such as polyethylene resin and polypropylene resin. Regarding electrolyte resistance, insulating members are required to have particularly excellent electrolyte resistance in high-temperature environments because batteries are increasingly used in high-temperature environments. Furthermore, in view of the rapid expansion of opportunities to utilize electrical energy in recent years, in addition to the above-mentioned properties, excellent moldability is also one of the properties required for insulating members.

For example, in Patent Document 1, as an insulating member using a resin other than polyolefin resin, a laminate of a phenolic resin containing glass cloth as a base material and an inorganic additive is used as an insulating plate to reduce the heat generated during overcharging. It is described that it is possible to suppress the curing shrinkage of the phenol resin caused by the phenol resin, and to prevent the deformation of the electrode plate group consisting of the positive electrode plate, the negative electrode plate, and the separator.

Patent Document 2 describes a secondary battery gasket using polyphenylene sulfide (hereinafter sometimes abbreviated as "PPS") resin. PPS resin is a resin with excellent heat resistance, chemical resistance, and mechanical properties, and can be molded into various molded products, fibers, films, etc. using various molding methods such as injection molding and extrusion molding, so it is used for electrical and electronic parts. It is put into practical use in a wide range of fields, including mechanical parts and automobile parts. On the other hand, PPS resin has a problem of poor toughness.

Therefore, in Patent Document 2, by adding a thermoplastic elastomer to PPS resin, toughness is imparted, stress relaxation is less likely to occur even when compressed under constant strain, and airtightness can be maintained for a long time. A gasket for secondary batteries is described.

In addition, Patent Document 3 describes the production of PPS resin with low metal content and volatile component generation and excellent molding stability by subjecting acid-treated PPS resin to a relatively mild thermal oxidation treatment. The method is described.

Japanese Patent Application Publication No. 2002-231314 Japanese Patent Application Publication No. 2011-29167 Japanese Patent Application Publication No. 2009-144141

However, since the material described in Patent Document 1 is produced by punching, there is a problem in terms of moldability.

Patent Document 2 discloses that as a thermoplastic elastomer is blended into PPS resin, the volatile components during melting increase, which leads to mold stains during injection molding and increases the frequency of mold maintenance. There are issues from a gender perspective. Furthermore, the volatile components generated may be eluted into the electrolytic solution, which may lead to deterioration of battery characteristics.

On the other hand, although the PPS resin described in Patent Document 3 has a low metal content and a small amount of volatile components generated and is excellent in molding stability, it is difficult to exhibit the toughness required for battery insulating members.

Therefore, an object of the present invention is to obtain an insulating member for a battery made of a polyphenylene sulfide resin composition that has excellent toughness, electrolyte resistance, heat resistance, and moldability.

The present inventors conducted studies to solve this problem, and found that an insulating member for a battery is made of a resin composition containing a polyphenylene sulfide resin, and the content of cyclic polyphenylene sulfide in the polyphenylene sulfide resin is 0. 01 to 1.0% by weight, and has a tensile elongation at break of 15% or more in a tensile test (ISO527-1, 2) of a test piece obtained by injection molding the resin composition. I ended up getting it.

That is, the present invention has been made to solve at least part of the above-mentioned problems, and can be implemented as the following embodiments.
(1) An insulating member for a battery, wherein the insulating member is made of a resin composition containing (a) polyphenylene sulfide resin, and the proportion of (a) polyphenylene sulfide resin in the resin composition is 89% by weight or more. , the content of cyclic polyphenylene sulfide in the polyphenylene sulfide resin (a) is 0.01 to 1.0% by weight, and a tensile test (ISO527-1, In 2), the insulating member for a battery has a tensile elongation at break of 15% or more.
(2) The insulating member for a battery according to (1), wherein the resin composition has a weight change of 0.5% by weight or less before and after being heated and melted at 320° C. for 120 minutes.
(3) The insulating member for a battery according to any one of (1) to (2), wherein the resin composition contains (b) polyethylene, and the content of (b) polyethylene is equal to or less than (a). ) An insulating member for a battery in an amount of 0.01 to 5.0 parts by weight based on 100 parts by weight of polyphenylene sulfide resin.
(4) The insulating member for a battery according to any one of (1) to (3), wherein the resin composition contains (c) a thermoplastic elastomer, and (c) the content of the thermoplastic elastomer. is less than 1 part by weight based on 100 parts by weight of the polyphenylene sulfide resin (a).
(5) The insulating member for a battery according to any one of (1) to (4), wherein the resin composition has a melt flow rate (according to JIS K7210, temperature: 315°C, load: 2160 g). An insulating member for a battery having a measured value of 10 to 80 g/10 minutes.
(6) The insulating member for a battery according to any one of (1) to (5), wherein the resin composition contains (d) an amorphous resin having a glass transition temperature of 150°C or higher; d) An insulating member for a battery, wherein the content of the amorphous resin having a glass transition temperature of 150° C. or higher is 0.1 to 11 parts by weight based on 100 parts by weight of the polyphenylene sulfide resin (a).
(7) The insulating member for a battery according to (6), wherein the amorphous resin (d) having a glass transition temperature of 150° C. or higher is polyethersulfone, polyetherimide, polyphenylene oxide, polyphenylene sulfone, polysulfone, and An insulating member for a battery comprising a resin composition of at least one selected from polycarbonate.
(8) The insulating member for a battery according to any one of (1) to (7), wherein the resin composition has an ash content of 1.0% by weight or less when incinerated at 550°C. An insulating material for a certain battery .

According to the present invention, it is possible to obtain an insulating member for a battery made of a polyphenylene sulfide resin composition that has excellent toughness, electrolyte resistance, heat resistance, and moldability.

FIG. 2 is a schematic diagram of a molded product used for evaluation of mold staining properties.

Embodiments of the present invention will be described in detail below.

(1) (a) Polyphenylene sulfide resin (a) PPS resin used in the present invention is a polymer having a repeating unit represented by the following structural formula,

From the viewpoint of heat resistance, a polymer containing 70 mol% or more, more preferably 90 mol% or more of a polymer containing a repeating unit represented by the above structural formula is preferable. Furthermore, less than 30 mol% of the repeating units in (a) PPS resin may be composed of repeating units having the following structure.

Since a PPS copolymer having a portion of such a structure has a low melting point, such a resin composition is advantageous in terms of moldability.

There is no particular restriction on the weight average molecular weight of the PPS resin (a) used in the present invention, but from the perspective of obtaining better mechanical properties, the weight average molecular weight is preferably 30,000 to 150,000, more preferably 40,000 to 130,000, and more preferably 45,000 to 110,000. is more preferable, and 50,000 to 90,000 is more preferable. If the weight average molecular weight is small, the mechanical properties of the PPS resin itself will deteriorate, so it is preferably 30,000 or more. On the other hand, if the weight average molecular weight exceeds 150,000, the melt viscosity becomes significantly large, which is an unfavorable tendency in molding.

The weight average molecular weight in the present invention is a value calculated in terms of polystyrene using gel permeation chromatography (GPC) manufactured by Senshu Kagaku.

Further, it is essential that the content of cyclic PPS in the PPS resin (a) used in the present invention is 0.01 to 1.0% by weight. In the present invention, by setting the content of cyclic PPS in the PPS resin in the range of 0.01 to 1.0% by weight, it is possible to improve electrolyte resistance in battery insulating members and to prevent mold contamination during molding. This is the first time I've discovered that it can be controlled. If the content of cyclic PPS in the PPS resin exceeds 1.0% by weight, it is not preferable because it leads to a decrease in electrolyte resistance and moldability. On the other hand, as for the lower limit of the content of cyclic PPS in the PPS resin, the lower the content, the better, and there is no particular restriction, but the lower limit is substantially about 0.01% by weight. In order to obtain a PPS resin with such an amount of cyclic PPS, for example, as described later, in the PPS manufacturing method, after the PPS polymerization reaction is completed, the particulate polymer is recovered by slow cooling, and then the particulate polymer is recovered using an organic solvent. Washing is preferred.

The content of cyclic PPS in the PPS resin in the present invention was determined using high performance liquid chromatography (HPLC) manufactured by Shimadzu Corporation.

The method for producing (a) PPS resin used in the present invention will be described below, but the method is not limited to the following method as long as (a) PPS resin having the above characteristics can be obtained.

First, the contents of the polyhalogenated aromatic compound, sulfidating agent, polymerization solvent, molecular weight regulator, polymerization aid, and polymerization stabilizer used in the production method will be explained.

[Polyhalogenated aromatic compound]
The polyhalogenated aromatic compound refers to a compound having two or more halogen atoms in one molecule. Specific examples include p-dichlorobenzene, m-dichlorobenzene, o-dichlorobenzene, 1,3,5-trichlorobenzene, 1,2,4-trichlorobenzene, 1,2,4,5-tetrachlorobenzene, and hexachlorobenzene. Polyhalogenated aromatics such as chlorobenzene, 2,5-dichlorotoluene, 2,5-dichloro-p-xylene, 1,4-dibromobenzene, 1,4-diiodobenzene, 1-methoxy-2,5-dichlorobenzene, etc. Among them, p-dichlorobenzene is preferably used. In addition, for the purpose of introducing carboxyl groups, dihalogenated aromatic compounds containing carboxyl groups such as 2,4-dichlorobenzoic acid, 2,5-dichlorobenzoic acid, 2,6-dichlorobenzoic acid, and 3,5-dichlorobenzoic acid are used. It is also one of the preferred embodiments to use compounds and mixtures thereof as copolymerization monomers, and it is also possible to combine two or more different polyhalogenated aromatic compounds to form a copolymer. Preferably, the main component is a p-dihalogenated aromatic compound.

The amount of the polyhalogenated aromatic compound to be used is from 0.9 to 2.0 mol, preferably from 0.95 to 1.0 mol per mol of the sulfidating agent, in order to obtain (a) PPS resin with a viscosity suitable for processing. For example, the amount is 5 mol, more preferably 1.005 to 1.2 mol.

[Sulfiding agent]
Sulfidating agents include alkali metal sulfides, alkali metal hydrosulfides, and hydrogen sulfide.

Specific examples of alkali metal sulfides include lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide, cesium sulfide, and mixtures of two or more of these, with sodium sulfide being preferably used. These alkali metal sulfides can be used as hydrates or aqueous mixtures or in anhydrous form.

Specific examples of alkali metal bisulfides include sodium bisulfide, potassium bisulfide, lithium bisulfide, rubidium bisulfide, cesium bisulfide, and mixtures of two or more of these. Among these, sodium bisulfide is Preferably used. These alkali metal hydrosulfides can be used as hydrates or aqueous mixtures or in anhydrous form.

Furthermore, an alkali metal sulfide prepared in situ in a reaction system from an alkali metal hydrosulfide and an alkali metal hydroxide can also be used. Alternatively, an alkali metal sulfide can be prepared from an alkali metal hydrosulfide and an alkali metal hydroxide, and the alkali metal sulfide can be transferred to a polymerization tank for use.

Alternatively, an alkali metal sulfide prepared in situ in a reaction system from an alkali metal hydroxide such as lithium hydroxide or sodium hydroxide and hydrogen sulfide can also be used. Alternatively, an alkali metal sulfide can be prepared from an alkali metal hydroxide such as lithium hydroxide or sodium hydroxide and hydrogen sulfide, and the alkali metal sulfide can be transferred to a polymerization tank for use.

The amount of sulfidating agent charged means the amount remaining after subtracting the loss from the actual amount of sulfidating agent, if a portion of the sulfidating agent is lost before the start of the polymerization reaction due to dehydration or the like.

In addition, it is also possible to use an alkali metal hydroxide and/or an alkaline earth metal hydroxide together with the sulfidating agent. Preferred examples of alkali metal hydroxides include sodium hydroxide, potassium hydroxide, lithium hydroxide, rubidium hydroxide, cesium hydroxide, and mixtures of two or more of these. Specific examples of metal hydroxides include calcium hydroxide, strontium hydroxide, barium hydroxide, etc. Among them, sodium hydroxide is preferably used.

When an alkali metal hydrosulfide is used as a sulfidating agent, it is particularly preferable to use an alkali metal hydroxide at the same time, and the amount used is 0.95 to 1. For example, the amount is 20 mol, preferably 1.00 to 1.15 mol, and more preferably 1.005 to 1.100 mol.

[Polymerization solvent]
It is preferable to use an organic polar solvent as the polymerization solvent. Specific examples include N-alkylpyrrolidones such as N-methyl-2-pyrrolidone and N-ethyl-2-pyrrolidone, caprolactams such as N-methyl-ε-caprolactam, and 1,3-dimethyl-2-imidazolidone. Examples include aprotic organic solvents such as non-, N,N-dimethylacetamide, N,N-dimethylformamide, hexamethylphosphoric triamide, dimethylsulfone, tetramethylene sulfoxide, and mixtures thereof. It is preferably used because of its high reaction stability. Among these, N-methyl-2-pyrrolidone (hereinafter sometimes abbreviated as NMP) is particularly preferably used.

The amount of the organic polar solvent used is selected in the range of 2.0 mol to 10 mol, preferably 2.25 mol to 6.0 mol, more preferably 2.5 mol to 5.5 mol per mol of the sulfidating agent. It will be done.

[Molecular weight regulator]
A monohalogen compound (not necessarily an aromatic compound) is added to the above-mentioned polyhalogenated aromatic compound in order to form the ends of the resulting (a) PPS resin or to adjust the polymerization reaction and molecular weight. Can be used together.

[Polymerization aid]
It is also one of the preferred embodiments to use a polymerization aid in order to obtain (a) PPS resin with a relatively high degree of polymerization in a shorter time. Here, the polymerization aid means a substance that has the effect of increasing the viscosity of the obtained (a) PPS resin. Specific examples of such polymerization aids include organic carboxylates, water, alkali metal chlorides, organic sulfonates, alkali metal sulfates, alkaline earth metal oxides, alkali metal phosphates, and alkaline earth metal oxides. Examples include similar metal phosphates. These may be used alone or in combination of two or more. Among these, organic carboxylates, water, and alkali metal chlorides are preferred, and the organic carboxylates are preferably alkali metal carboxylates, and the alkali metal chlorides are lithium chloride.

The alkali metal carboxylate has the general formula R(COOM) _n (wherein R is an alkyl group, cycloalkyl group, aryl group, alkylaryl group, or arylalkyl group having 1 to 20 carbon atoms. M is an alkali metal selected from lithium, sodium, potassium, rubidium and cesium; n is an integer from 1 to 3). Alkali metal carboxylates can also be used as hydrates, anhydrides or aqueous solutions. Specific examples of alkali metal carboxylates include lithium acetate, sodium acetate, potassium acetate, sodium propionate, lithium valerate, sodium benzoate, sodium phenylacetate, potassium p-toluate, and mixtures thereof. can be mentioned.

An alkali metal carboxylate is produced by adding approximately equal chemical equivalents of an organic acid and one or more compounds selected from the group consisting of alkali metal hydroxides, alkali metal carbonates, and alkali metal bicarbonates and reacting them. It may be formed by. Among the alkali metal carboxylates mentioned above, lithium salts have high solubility in the reaction system and have a large auxiliary effect, but are expensive, while potassium, rubidium, and cesium salts have insufficient solubility in the reaction system. Therefore, sodium acetate, which is inexpensive and has appropriate solubility in the polymerization system, is most preferably used.

When using these alkali metal carboxylates as polymerization aids, the amount used is usually in the range of 0.01 mol to 2 mol per 1 mol of the charged alkali metal sulfide, and in the sense of obtaining a higher degree of polymerization, The range is preferably from 0.1 mol to 0.6 mol, and more preferably from 0.2 mol to 0.5 mol.

In addition, when water is used as a polymerization aid, the amount added is usually in the range of 0.3 to 15 moles per mole of the charged alkali metal sulfide, and in order to obtain a higher degree of polymerization, the amount added is 0.6 moles. The range is preferably from 1 mol to 10 mol, and more preferably from 1 mol to 5 mol.

It is of course possible to use two or more of these polymerization aids in combination; for example, if an alkali metal carboxylate and water are used in combination, it is possible to increase the molecular weight with smaller amounts of each.

There is no particular specification regarding the timing of addition of these polymerization aids, and they may be added at any time during the pre-process described below, at the start of polymerization, or during polymerization, or may be added in multiple portions. When using an alkali metal carboxylate as a polymerization aid, it is more preferable to add it simultaneously at the start of the previous step or at the start of the polymerization because addition is easy. When water is used as a polymerization aid, it is effective to add it during the polymerization reaction after charging the polyhalogenated aromatic compound.

[Polymerization stabilizer]
A polymerization stabilizer can also be used to stabilize the polymerization reaction system and prevent side reactions. The polymerization stabilizer contributes to stabilizing the polymerization reaction system and suppresses undesirable side reactions. One measure of side reactions is the production of thiophenol, and the production of thiophenol can be suppressed by adding a polymerization stabilizer. Specific examples of polymerization stabilizers include compounds such as alkali metal hydroxides, alkali metal carbonates, alkaline earth metal hydroxides, and alkaline earth metal carbonates. Among these, alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, and lithium hydroxide are preferred. The alkali metal carboxylates mentioned above also act as polymerization stabilizers. Furthermore, when using an alkali metal hydrosulfide as a sulfidating agent, it is particularly preferable to use an alkali metal hydroxide at the same time. Oxides can also serve as polymerization stabilizers.

These polymerization stabilizers can be used alone or in combination of two or more. The polymerization stabilizer is used in a proportion of usually 0.02 to 0.2 mol, preferably 0.03 to 0.1 mol, more preferably 0.04 to 0.09 mol, per 1 mol of the charged alkali metal sulfide. It is preferable to use it in If this proportion is too small, the stabilizing effect will be insufficient, and if it is too large, it will be economically disadvantageous or the polymer yield will tend to decrease.

There is no particular specification as to when to add the polymerization stabilizer; it may be added at any time during the pre-process, at the start of polymerization, or during polymerization, which will be described later.Also, it may be added in multiple parts, but It is more preferable to add it simultaneously at the start of the process or at the start of polymerization because it is easy to add.

Next, a preferred method for producing PPS resin (a) used in the present invention will be specifically explained in order, including a pre-process, a polymerization reaction process, a recovery process, and a post-treatment process, but it is of course not limited to this method. It's not something you can do.

[pre-process]
(a) In the method for producing PPS resin, the sulfidating agent is usually used in the form of a hydrate, but before adding the polyhalogenated aromatic compound, the mixture containing the organic polar solvent and the sulfidating agent is heated. It is preferable to warm the temperature and remove excess water from the system.

Furthermore, as mentioned above, a sulfidating agent prepared from an alkali metal hydrosulfide and an alkali metal hydroxide in situ in the reaction system or in a tank different from the polymerization tank may also be used. I can do it. Although there are no particular limitations on this method, it is preferable to add an alkali metal hydrosulfide and an alkali metal hydroxide to an organic polar solvent under an inert gas atmosphere at a temperature ranging from room temperature to 150°C, preferably from room temperature to 100°C. In addition, there is a method in which the temperature is raised to at least 150°C or higher, preferably 180 to 260°C, under normal pressure or reduced pressure, and water is distilled off. A polymerization aid may be added at this stage. Further, in order to promote distillation of water, toluene or the like may be added to carry out the reaction.

In the polymerization reaction, the amount of water in the polymerization system is preferably 0.3 to 10.0 moles per mole of the charged sulfidating agent. Here, the amount of water within the polymerization system is the amount obtained by subtracting the amount of water removed from the polymerization system from the amount of water charged into the polymerization system. Further, the water to be charged may be in any form such as water, an aqueous solution, or crystal water.

[Polymerization reaction process]
(a) PPS resin is produced by reacting a sulfidating agent and a polyhalogenated aromatic compound in an organic polar solvent within a temperature range of 200°C or higher and lower than 290°C.

When starting the polymerization reaction step, the organic polar solvent, the sulfidating agent, and the polyhalogenated aromatic compound are preferably mixed at a temperature range of room temperature to 240°C, preferably 100°C to 230°C, under an inert gas atmosphere. do. A polymerization aid may be added at this stage. These raw materials may be added in any order or at the same time.

Such mixtures are generally heated to a temperature in the range of 200°C to less than 290°C. Although there is no particular restriction on the heating rate, a rate of 0.01 to 5°C/min is usually selected, and a range of 0.1 to 3°C/min is more preferable.

Generally, the temperature is finally raised to a temperature below 250 to 290°C, and the reaction is carried out at that temperature for usually 0.25 to 50 hours, preferably 0.5 to 20 hours.

A method of reacting at 200° C. to 260° C. for a certain period of time before reaching the final temperature and then raising the temperature to below 270° C. to 290° C. is effective in obtaining a higher degree of polymerization. At this time, the reaction time at 200° C. to 260° C. is usually selected in the range of 0.25 hours to 20 hours, preferably in the range of 0.25 hours to 10 hours.

Note that in order to obtain a polymer with a higher degree of polymerization, it may be effective to perform polymerization in multiple stages. When polymerization is carried out in multiple stages, it is effective to perform the polymerization at a point when the conversion rate of the polyhalogenated aromatic compound in the system at 245° C. reaches 40 mol% or more, preferably 60 mol%.

Note that the conversion rate of the polyhalogenated aromatic compound (herein abbreviated as PHA) is a value calculated using the following formula. The residual amount of PHA can usually be determined by gas chromatography.

(A) When polyhalogenated aromatic compound is added in excess molar ratio to alkali metal sulfide Conversion rate = [PHA charged amount (mol) - PHA remaining amount (mol)] / [PHA charged amount (mol) - Excess amount of PHA (mol)].

(B) Cases other than the above (A) Conversion rate = [PHA charged amount (mol) - PHA remaining amount (mol)]/[PHA charged amount (mol)].

[Collection process]
(a) In the method for producing PPS resin, solid matter is recovered from the polymerization reaction product containing the polymer, solvent, etc. after completion of polymerization. As for the recovery method, it is essential to adopt a method of slowly cooling and recovering the particulate polymer after the polymerization reaction is completed. There is no particular limit to the slow cooling rate at this time, but it is usually about 0.1°C/min to 3°C/min. It is not necessary to perform slow cooling at the same rate in all steps of the slow cooling process, but methods such as slow cooling at a rate of 0.1 to 1°C/min until the polymer particles crystallize and precipitate, and then at a speed of 1°C/min or more are recommended. May be adopted.

[Post-processing process]
(a) The PPS resin may be produced through the above polymerization and recovery steps and then subjected to acid treatment, hot water treatment, washing with an organic solvent, and alkali metal or alkaline earth metal treatment.

The case where acid treatment is performed is as follows. (a) The acid used for the acid treatment of PPS resin is not particularly limited as long as it does not have the effect of decomposing the PPS resin, such as acetic acid, hydrochloric acid, sulfuric acid, phosphoric acid, silicic acid, carbonic acid, and propylic acid. Among these, acetic acid and hydrochloric acid are more preferably used, but those that decompose and deteriorate the (a) PPS resin, such as nitric acid, are not preferred.

The acid treatment may be carried out by immersing (a) the PPS resin in an acid or an aqueous solution of the acid, and stirring or heating may be carried out as necessary. For example, when using acetic acid, a sufficient effect can be obtained by immersing the PPS resin powder in an aqueous solution of pH 4 heated to 80 to 200° C. and stirring for 30 minutes. The pH after treatment may be 4 or more, for example, about pH 4 to 8. The acid-treated PPS resin (a) is preferably washed several times with water or hot water to remove residual acids or salts. The water used for washing is preferably distilled water or deionized water in the sense that it does not impair the preferable chemical modification effect of (a) PPS resin by acid treatment.

When performing hot water treatment, the procedure is as follows. (a) When treating the PPS resin with hot water, the temperature of the hot water is preferably 100°C or higher, more preferably 120°C or higher, even more preferably 150°C or higher, particularly preferably 170°C or higher. If the temperature is less than 100°C, the effect of (a) the preferable chemical modification of the PPS resin will be small, which is not preferable.

In order to achieve the desired effect of (a) chemical modification of the PPS resin by hot water washing, the water used is preferably distilled water or deionized water. There are no particular restrictions on the operation of hot water treatment, and it can be carried out by adding a predetermined amount of (a) PPS resin to a predetermined amount of water, heating and stirring it in a pressure vessel, or continuously performing hot water treatment. be exposed. As for the ratio of (a) PPS resin to water, it is preferable that there is more water, but usually a bath ratio of 200 g or less of (a) PPS resin per 1 liter of water is selected.

Furthermore, since decomposition of terminal groups is undesirable, the treatment atmosphere is preferably an inert atmosphere to avoid this. Furthermore, it is preferable that the (a) PPS resin that has undergone this hot water treatment operation be washed several times with warm water in order to remove any remaining components.

When washing with an organic solvent, the procedure is as follows. (a) The organic solvent used for washing the PPS resin is not particularly limited as long as it does not have the effect of decomposing the PPS resin, such as N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, Nitrogen-containing polar solvents such as 1,3-dimethylimidazolidinone, hexamethylphosphorusamide, and piperazinones, sulfoxide/sulfone solvents such as dimethyl sulfoxide, dimethyl sulfone, and sulfolane, and ketones such as acetone, methyl ethyl ketone, diethyl ketone, and acetophenone. ether solvents such as dimethyl ether, dipropyl ether, dioxane, tetrahydrofuran, chloroform, methylene chloride, trichloroethylene, ethylene dichloride, perchloroethylene, monochloroethane, dichloroethane, tetrachloroethane, perchlorethane, chlorobenzene, etc. Halogenated solvents, alcohol/phenolic solvents such as methanol, ethanol, propanol, butanol, pentanol, ethylene glycol, propylene glycol, phenol, cresol, polyethylene glycol, polypropylene glycol, and aromatic hydrocarbons such as benzene, toluene, and xylene. Examples include solvents. Among these organic solvents, use of N-methyl-2-pyrrolidone, acetone, dimethylformamide, chloroform, and the like is particularly preferred. Further, these organic solvents may be used alone or in combination of two or more.

As a method for washing with an organic solvent, there is a method such as immersing the (a) PPS resin in an organic solvent, and it is also possible to stir or heat the resin as appropriate. There are no particular restrictions on the cleaning temperature when (a) PPS resin is washed with an organic solvent, and any temperature from room temperature to about 300°C can be selected. Although the higher the cleaning temperature, the higher the cleaning efficiency tends to be, usually a cleaning temperature of room temperature to 150° C. can be sufficiently effective. It is also possible to wash under pressure in a pressure vessel at a temperature above the boiling point of the organic solvent. Furthermore, there is no particular restriction on the cleaning time. Although it depends on the cleaning conditions, in the case of batch cleaning, sufficient effects can usually be obtained by cleaning for 5 minutes or more. It is also possible to wash continuously.

Methods for treating alkali metals and alkaline earth metals include adding an alkali metal salt or alkaline earth metal salt before, during, or after the preceding step, before the polymerization step, during the polymerization step, or during the polymerization step. Examples include a method in which an alkali metal salt or an alkaline earth metal salt is added later into the polymerization reactor, or a method in which an alkali metal salt or an alkaline earth metal salt is added at the beginning, middle, or end of the washing step. Among them, the easiest method is to remove residual oligomers and salts by washing with an organic solvent or hot water or hot water, and then add an alkali metal salt or alkaline earth metal salt. The alkali metals and alkaline earth metals are preferably introduced into PPS in the form of alkali metal ions and alkaline earth metal ions such as acetates, hydroxides, and carbonates. Further, it is preferable to remove excess alkali metal salts and alkaline earth metal salts by washing with hot water or the like. The concentration of alkali metal ions and alkaline earth metal ions when introducing the alkali metal and alkaline earth metal is preferably 0.001 mmol or more, more preferably 0.01 mmol or more per 1 g of PPS. The temperature is preferably 50°C or higher, more preferably 75°C or higher, and particularly preferably 90°C or higher. Although there is no particular upper limit temperature, from the viewpoint of operability, 280° C. or lower is usually preferable. The bath ratio (the weight of cleaning liquid to the weight of dry PPS) is preferably 0.5 or more, more preferably 3 or more, and even more preferably 5 or more.

In the present invention, from the viewpoint of obtaining a polyphenylene sulfide resin composition with excellent retention stability, residual oligomers and residual salts are removed by repeating organic solvent washing and hot water at about 80° C. or the above-mentioned hot water washing several times. Afterwards, a method of acid treatment or treatment with an alkali metal salt or alkaline earth metal salt is preferred, and a method of treatment with an alkali metal salt or alkaline earth metal salt is particularly preferred.

In addition, the PPS resin (a) can also be used after the polymerization is completed by heating it in an oxygen atmosphere and by thermal oxidative crosslinking treatment by adding a crosslinking agent such as peroxide and heating to increase the molecular weight.

When dry heat treatment is performed for the purpose of increasing the molecular weight by thermal oxidative crosslinking, the temperature is preferably 160 to 260°C, more preferably 170 to 250°C. Further, the oxygen concentration is preferably 5% by volume or more, more preferably 8% by volume or more. There is no particular upper limit to the oxygen concentration, but the upper limit is about 50% by volume. The treatment time is preferably 0.5 to 100 hours, more preferably 1 to 50 hours, and even more preferably 2 to 25 hours. The heat treatment device may be a normal hot air dryer, or a rotating type or heating device with stirring blades, but for efficient and more uniform treatment, a rotating type or heating device with stirring blades is recommended. More preferably, a device is used.

It is also possible to perform dry heat treatment for the purpose of suppressing thermal oxidative crosslinking and removing volatile components. The temperature is preferably in the range of 130 to 250°C, more preferably in the range of 160 to 250°C. Further, the oxygen concentration in this case is desirably less than 5% by volume, more preferably less than 2% by volume. The treatment time is preferably 0.5 to 50 hours, more preferably 1 to 20 hours, and even more preferably 1 to 10 hours. The heat treatment device may be a normal hot air dryer, or a rotating type or heating device with stirring blades, but for efficient and more uniform treatment, a rotating type or heating device with stirring blades is recommended. More preferably, a device is used.

However, from the viewpoint of exhibiting excellent toughness, the PPS resin (a) of the present invention is either a substantially linear PPS resin that is not subjected to high molecular weight through thermal oxidative crosslinking treatment, or is lightly oxidative crosslinked. A semi-crosslinked PPS resin is preferable, and a substantially linear PPS resin is more preferable. Further, in the present invention, a plurality of (a) PPS resins having different melt viscosities may be mixed and used.

In a preferred embodiment, (a) the PPS resin of the present invention contains 25 to 400 μmol/g of carboxyl groups from the viewpoint of improving compatibility with (d) an amorphous resin having a glass transition temperature of 150° C. or higher. The carboxyl group content is more preferably from 25 to 250 μmol/g, even more preferably from 30 to 150 μmol/g, even more preferably from 30 to 80 μmol/g. If the amount of carboxyl groups in the PPS resin is less than 25 μmol/g, it is not preferable because (d) interaction with the amorphous resin having a glass transition temperature of 150° C. or higher tends to decrease. On the other hand, if the carboxyl group content of the PPS resin exceeds 400 μmol/g, it is not preferable because the volatile content in the processing step increases.

(a) Methods for introducing carboxyl groups into PPS resin include copolymerizing polyhalogenated aromatic compounds containing carboxyl groups, or adding compounds containing carboxyl groups, such as maleic anhydride and sorbic acid. Examples include (a) a method in which the resin is introduced by reacting with the PPS resin while melt-kneading.

(2) (b) Polyethylene It is preferable to mix (b) polyethylene into the PPS resin composition that constitutes the battery insulating member of the embodiment of the present invention. (b) The blending of polyethylene improves mold releasability during injection molding, which leads to a shortening of the molding cycle and can be expected to improve molding processability.

The blending amount of (b) polyethylene used in the present invention is preferably 0.01 to 5.0 parts by weight based on 100 parts by weight of (a) polyphenylene sulfide resin. The amount is preferably 0.05 to 3.0 parts by weight, more preferably 0.1 to 1.0 parts by weight. (b) It is preferable to set the blending amount of polyethylene to 5.0 parts by weight or less, since gas generation during molding can be suppressed and mold staining can be suppressed. (b) It is preferable that the blending amount of polyethylene is 0.01 parts by weight or more because the effect as a mold release agent is sufficiently exhibited and moldability is improved.

(3) (c) Thermoplastic elastomer Generally, for the purpose of improving the toughness of (a) PPS resin, (c) thermoplastic elastomer is blended. However, in the present invention, it is preferable to avoid blending the thermoplastic elastomer (c) as much as possible in order to obtain good moldability and electrolyte resistance.

If (c) thermoplastic elastomer is blended, the content of (c) thermoplastic elastomer in the embodiment of the present invention is less than 1 part by weight based on 100 parts by weight of (a) polyphenylene sulfide resin. The amount is preferably less than 0.8 parts by weight, more preferably less than 0.5 parts by weight. Moreover, it is particularly preferable not to mix (c) a thermoplastic elastomer. (c) If the content of the thermoplastic elastomer exceeds 1 part by weight, volatile components during heating and melting of the PPS resin composition will increase, which is unfavorable from the viewpoint of electrolyte resistance and moldability.

Examples of the thermoplastic elastomer (c) include ethylene-butene copolymer, ethylene-propylene copolymer, ethylene-hexene copolymer, ethylene-octene copolymer, ethylene-vinyl acetate copolymer, and ethylene-acrylic acid. Methyl copolymer, ethylene-ethyl acrylate copolymer, ethylene-glycidyl methacrylate copolymer, ethylene-butyl acrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-styrene copolymer, ethylene-acrylic acid Examples include methyl-glycidyl methacrylate copolymer, ethylene-ethyl acrylate-glycidyl methacrylate copolymer, and ethylene-vinyl acetate-glycidyl methacrylate copolymer.

(c) Thermoplastic elastomer used in the present invention contains a reactive functional group from the viewpoint of forming an intermolecular bond with (a) PPS resin or (d) amorphous resin with a glass transition temperature of 150°C or higher. It is also mentioned as a preferable embodiment.

The reactive functional groups that the thermoplastic elastomer has are not particularly limited, and specifically include vinyl groups, epoxy groups, carboxyl groups, acid anhydride groups, ester groups, aldehyde groups, carbonyldioxy groups, haloformyl groups, Examples include alkoxycarbonyl groups, amino groups, hydroxyl groups, styryl groups, methacrylic groups, acrylic groups, ureido groups, mercapto groups, sulfide groups, isocyanate groups, hydrolyzable silyl groups, among others, hydroxyl groups, epoxy groups, carboxyl groups, Amino groups, acid anhydride groups, and isocyanate groups are preferred, and two or more types of these reactive functional groups may be included.

(c) Methods for introducing a reactive functional group into a thermoplastic elastomer include (c) a method of blending a compound or resin that is compatible with the thermoplastic elastomer and contains the functional group; (c) a method of copolymerizing a thermoplastic elastomer with a polymerizable monomer containing the above-mentioned functional group or containing a functional group convertible to the above-mentioned functional group in the main chain, side chain, or terminal when polymerizing the thermoplastic elastomer; (c) a thermoplastic elastomer and a thermoplastic elastomer containing the functional group or convertible to the functional group; Examples include a method in which a polymerizable monomer containing a functional group is reacted in the presence of a radical generator, and (c) a method in which a thermoplastic elastomer is modified by methods such as oxidation and thermal decomposition. Among these, (c) when polymerizing a thermoplastic elastomer, a method of copolymerizing a polymerizable monomer containing the above-mentioned functional group or containing a functional group convertible to the above-mentioned functional group in the main chain, side chain or terminal; and (c) any method selected from the group consisting of reacting a thermoplastic elastomer with a polymerizable monomer containing the functional group or a functional group convertible into the functional group in the presence of a radical generator. This method is preferable from the viewpoints of quality, cost, and control of the amount introduced.

The polymerizable monomer containing the functional group is not particularly limited, but includes, for example, acrylic acid, methacrylic acid, maleic acid, itaconic acid, citraconic acid, crotonic acid, hymic acid, acid anhydrides thereof, and acrylic acid. Examples include glycidyl, glycidyl methacrylate, glycidyl ethyl acrylate, glycidyl itaconate, vinyl acetate, vinyl propionate, vinyltrimethoxysilane, vinyltriethoxysilane, and γ-methacryloxypropyltrimethoxysilane.

(4) (d) Amorphous resin with a glass transition temperature of 150°C or higher The PPS resin composition constituting the battery insulating member of the embodiment of the present invention includes (d) an amorphous resin with a glass transition temperature of 150°C or higher. It is effective to blend resin. By blending (d) an amorphous resin with a glass transition temperature of 150° C. or higher into the PPS resin, it is expected that toughness, which is an essential issue of PPS resin, will be improved. On the other hand, an amorphous resin having a glass transition temperature of less than 150° C. has insufficient heat resistance and increases the amount of volatile components generated during heating and melting of the PPS resin composition, which is unfavorable from the viewpoint of moldability.

Examples of the amorphous resin (d) having a glass transition temperature of 150°C or higher used in the present invention include polyethersulfone, polyetherimide, polyphenylene oxide, polyphenylene sulfone, polysulfone, polycarbonate, polyarylate, polyimide, polyamideimide, etc. can. Among these, polyether sulfone, polyetherimide, polyphenylene oxide, polyphenylene sulfone, polysulfone, and polycarbonate are preferred. It is also possible to use two or more of these (d) amorphous resins having a glass transition temperature of 150° C. or higher.

The blending amount of (d) amorphous resin having a glass transition temperature of 150°C or higher used in the present invention is preferably 0.1 to 30 parts by weight, and 1 to 25 parts by weight based on 100 parts by weight of (a) PPS resin. parts by weight, and even more preferably 2 to 15 parts by weight. (d) If the amount of the amorphous resin with a glass transition temperature of 150°C or higher is less than 0.1 part by weight, the toughness improvement effect will be insufficient, and if it exceeds 30 parts by weight, the electrolyte resistance will decrease. Therefore, it is undesirable.

(5) (e) Other additives Furthermore, the PPS resin composition constituting the battery insulating member of the embodiment of the present invention contains (a) PPS resin, (b) within the range that does not impair the effects of the present invention. Resins other than polyethylene, (c) a thermoplastic elastomer, and (d) an amorphous resin having a glass transition temperature of 150° C. or higher may be added and blended. Specific examples include polyamide, polybutylene terephthalate, polyethylene terephthalate, polyketone, liquid crystal polymer, polyetherketone, polyetheretherketone, fluororesin (polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene copolymer (ETFE) ), tetrafluoroethylene-perfluoro(alkyl vinyl ether) copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), ethylene-tetrafluoroethylene-hexafluoropropylene copolymer, polyvinylidene fluoride ( Examples include, but are not limited to, PVDF) and polychlorotrifluoroethylene (PCTFE).

In the PPS resin composition constituting the battery insulating member of the embodiment of the present invention, (a) the amount of phosphorus oxoacid metal salt blended is less than 0.01 part by weight with respect to 100 parts by weight of the PPS resin; is preferable, and more preferably less than 0.005 part by weight. By blending the phosphorus oxoacid metal salt, (b) it is possible to suppress the oxidative decomposition of polyethylene and to suppress the mold staining during molding, but when the blending amount is 0.01 part by weight or more, the PPS resin This is because the melt viscosity of the composition increases significantly, which tends to be unfavorable in the molding process of thin-walled battery insulating members. Most preferably, it does not contain phosphorus oxoacid metal salts.

Examples of phosphorus oxoacid metal salts include hypophosphorous acid, phosphorous acid, phosphoric acid, phosphinic acid, phosphonic acid, diphosphoric acid, and triphosphoric acid. Specifically, potassium hypophosphite, sodium hypophosphite, calcium hypophosphite, potassium phosphinate, sodium phosphinate, calcium phosphinate, aluminum phosphinate, aluminum diethylphosphinate, zinc phosphinate, magnesium phosphinate, etc. Can be mentioned.

Further, for the purpose of modification, the following compounds can be added. Plasticizers such as polyalkylene oxide oligomer compounds, thioether compounds, ester compounds, organic phosphorus compounds, organic phosphorus compounds, crystal nucleating agents such as polyether ether ketone, montan acid waxes, lithium stearate, aluminum stearate metal soaps such as ethylenediamine/stearic acid/sebacic acid polycondensates, mold release agents such as silicone compounds, and other usual additives such as water, lubricants, ultraviolet inhibitors, coloring inhibitors, colorants, and foaming agents. can be blended. If any of the above-mentioned compounds exceeds 10 parts by weight of the entire composition, the inherent characteristics of the PPS resin composition of the present invention will be impaired, so it is not preferable, and it is preferably added in an amount of 5 parts by weight or less, more preferably 1 part by weight or less.

Further, in the present invention, a compatibilizer can be used in combination for the purpose of increasing the compatibility between each resin. Specifically, epoxy resins and organic silane compounds can be used.

Specific examples of such epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, brominated epoxy resin, special skeleton bifunctional epoxy resin having a biphenyl skeleton or naphthalene skeleton, cresol novolac type, trisphenol methane type, Glycidyl ether type epoxy resins are represented by polyfunctional epoxy resins such as dicyclopentadiene type, glycidyl amine type epoxy resins are represented by aromatic amine type and aminophenol type, and hydrophthalic acid type and dimer acid type are represented. Examples include glycidyl ester type epoxy resins.

The amount of the epoxy resin added is preferably 0.1 to 5 parts by weight, particularly preferably 0.2 to 3 parts by weight, based on a total of 100 parts by weight of the PPS resin composition.

Specific examples of such organic silane compounds include epoxy group-containing compounds such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. Alkoxysilane compounds, γ-mercaptopropyltrimethoxysilane, mercapto group-containing alkoxysilane compounds such as γ-mercaptopropyltriethoxysilane, γ-ureidopropyltriethoxysilane, γ-ureidopropyltrimethoxysilane, γ-(2- ureido group-containing alkoxysilane compounds such as ureidoethyl)aminopropyltrimethoxysilane, γ-isocyanatepropyltriethoxysilane, γ-isocyanatepropyltrimethoxysilane, γ-isocyanatepropylmethyldimethoxysilane, γ-isocyanatepropylmethyldiethoxysilane, Isocyanate group-containing alkoxysilane compounds such as γ-isocyanatepropylethyldimethoxysilane, γ-isocyanatepropylethyldiethoxysilane, γ-isocyanatepropyltrichlorosilane, γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, -aminoethyl)aminopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, and other amino group-containing alkoxysilane compounds.Among them, from the viewpoint of reactivity, epoxy group-containing alkoxysilane compounds, Amino group-containing alkoxysilane compounds and isocyanate-containing alkoxysilane compounds are preferred, and isocyanate group-containing alkoxysilane compounds are particularly preferred. Excellent reactivity means that it leads to the development of excellent toughness and mold staining resistance.

The amount of the organic silane compound added is preferably 0.2 to 5 parts by weight, particularly preferably 0.2 to 3 parts by weight, based on a total of 100 parts by weight of the PPS resin composition. Further, 0.2 to 2 parts by weight is preferred. When the amount of the organic silane compound added is 0.2 parts by weight or more, not only can the effect of improving toughness be sufficiently obtained, but also the generation of burrs and mold staining during molding can be suppressed. When the amount of the organic silane compound added is 5 parts by weight or more, although the effect of improving toughness can be obtained, the amount of gas generated increases, leading to mold fouling, and the melt viscosity increases significantly, making it difficult to use thin-walled battery insulating materials. This is not preferable because it may make injection molding difficult.

The PPS resin composition constituting the battery insulating member of the embodiment of the present invention may contain an inorganic filler, although it is not an essential component, to the extent that the effects of the present invention are not impaired. Specific examples of such inorganic fillers include glass fibers, carbon fibers, carbon nanotubes, carbon nanohorns, potassium titanate whiskers, zinc oxide whiskers, calcium carbonate whiskers, wollastenite whiskers, aluminum borate whiskers, aramid fibers, alumina fibers, and silicon carbide fibers. , fibrous fillers such as ceramic fibers, asbestos fibers, gypsum fibers, metal fibers, or fullerenes, talc, wollastenite, zeolite, sericite, mica, kaolin, clay, pyrophyllite, silica, bentonite, asbestos, alumina. Silicates such as silicates, metal compounds such as silicon oxide, magnesium oxide, alumina, zirconium oxide, titanium oxide, iron oxide, carbonates such as calcium carbonate, magnesium carbonate, dolomite, sulfates such as calcium sulfate and barium sulfate, water Hydroxides such as calcium oxide, magnesium hydroxide, and aluminum hydroxide, glass beads, glass flakes, glass powder, ceramic beads, boron nitride, silicon carbide, carbon black, and non-fibrous fillers such as silica and graphite are used. Among them, glass fiber, silica, and calcium carbonate are preferable, and calcium carbonate and silica are particularly preferable from the viewpoint of anticorrosion and lubricant effects. Further, these inorganic fillers may be hollow, and two or more types can be used in combination. Further, these inorganic fillers may be used after being pretreated with a coupling agent such as an isocyanate compound, an organic silane compound, an organic titanate compound, an organic borane compound, or an epoxy compound. Among them, calcium carbonate, silica, and carbon black are preferable from the viewpoint of anticorrosive properties and lubricating materials.

The amount of the inorganic filler to be blended is selected to be less than 30 parts by weight, preferably less than 20 parts by weight, and more preferably less than 10 parts by weight, based on a total of 100 parts by weight of the PPS resin composition. A range of 5 parts by weight or less is more preferable. There is no particular lower limit, but 0.0001 parts by weight or more is preferable. While blending an inorganic filler is effective in improving the strength of the material, blending in an amount exceeding 30 parts by weight is not preferred because it results in a decrease in toughness.

(6) Method for manufacturing resin composition As a method for manufacturing the PPS resin composition constituting the battery insulating member of the embodiment of the present invention, manufacturing in a molten state, manufacturing in a solution state, etc. can be used. From the viewpoint of simplicity, production in a molten state is preferably used. For production in a molten state, melt-kneading using an extruder, melt-kneading using a kneader, etc. can be used, but from the viewpoint of productivity, melt-kneading using an extruder, which allows continuous production, is preferably used. For melt-kneading using an extruder, at least one extruder such as a single-screw extruder, a twin-screw extruder, a multi-screw extruder such as a four-screw extruder, or a twin-screw single-screw composite extruder can be used, but the kneading performance From the viewpoint of improving reactivity and productivity, multi-screw extruders such as a twin-screw extruder and a four-screw extruder can be preferably used, and melt-kneading using a twin-screw extruder is most preferred.

More specific melt-kneading methods include, but are not limited to, L/D (L: screw length, D: screw diameter) of 10 or more, preferably 20 or more, and kneading. It is preferable to use a twin-screw extruder having two or more, preferably three or more parts. Although there is no particular restriction on the upper limit of L/D, it is preferably 60 or less from the viewpoint of economic efficiency. Further, the upper limit of the number of kneading parts is not particularly limited, but from the viewpoint of productivity, it is preferably 10 or less. The ratio of the kneading portion to the total length of the screw is preferably 15% or more, more preferably 20% or more, and even more preferably 30% or more. If the ratio of the kneading part to the total length of the screw is less than 15%, the kneading force will be poor, and the number average dispersion diameter of (c) thermoplastic elastomer and (d) amorphous resin with a glass transition temperature of 150°C or higher will be coarse. and it is difficult to develop the desired physical properties. On the other hand, the upper limit of the ratio of the kneading part to the total length of the screw is preferably 70% or less from the viewpoint of preventing deterioration of the resin due to excessive shear heat generation during kneading.

It is preferable to knead at a screw rotation speed of 150 to 1000 revolutions/min, preferably 300 to 1000 revolutions/min, and more preferably 350 to 800 revolutions/min. When the screw rotation speed exceeds 150 rpm, the kneading force is sufficient, so that the number average dispersion diameter of (c) thermoplastic elastomer and (d) amorphous resin with a glass transition temperature of 150 ° C. or higher becomes fine. , leading to the development of desired toughness. (e) As an example of other additives, when an organic silane compound is added, the reaction occurs sufficiently, leading to the development of desired toughness and mold stain resistance. If the screw rotation speed exceeds 1000 rpm, resin and additives will deteriorate due to excessive shear heat generated during kneading, resulting in decreased toughness, reduced mold fouling resistance, and burr formation due to decreased melt viscosity. This is not preferable because it also leads to deterioration of molding processability. In addition, by setting the screw rotation speed high within this range, it is possible to reduce the melt viscosity while maintaining toughness, which improves the fluidity during injection molding of thin-walled battery insulation members. This is a favorable trend from the viewpoint of moldability.

The preferred range of cylinder temperature (°C) is the highest melting point or glass transition temperature of (a) PPS resin, (c) thermoplastic elastomer, and (d) amorphous resin with a glass transition temperature of 150°C or higher. A temperature range of +5 to 100°C of the melting point or glass transition temperature is desirable, specifically a range of 280 to 400°C, more preferably a range of 280 to 360°C, and even more preferably a range of 280 to 330°C.

There are no particular restrictions on the mixing order of the raw materials when melt-kneading, but there are methods such as blending all the raw materials and then melt-kneading them by the above method, blending some raw materials and then melt-kneading them by the above method, Either method can be used, such as a method in which the remaining raw materials are further blended and melt-kneaded, or a method in which after blending some of the raw materials, a side feeder is used to mix the remaining raw materials while melt-kneading is performed using a twin-screw extruder. may also be used.

(7) PPS resin composition The PPS resin composition constituting the battery insulating member of the embodiment of the present invention has a tensile elongation at break in a tensile test (ISO527-1, 2) of a test piece obtained by injection molding. It is 15% or more. It is more preferably 20% or more, and even more preferably 25% or more. A tensile elongation at break of 15% or more means that the PPS resin composition has excellent toughness, and when used in the form of an insulating member for batteries, it suppresses cracking during actual use and maintains insulation properties. This is essential from the perspective of ensuring safety. Regarding the upper limit of the tensile elongation at break, the higher the elongation, the better, and there is no particular restriction, but the upper limit is practically about 300%. In order to obtain a PPS resin composition having such a tensile elongation at break, preferable examples include a method of adding an epoxy resin or an organic silane compound, and a method of adding an amorphous resin having a glass transition temperature of 150° C. or higher. .

The PPS resin composition constituting the battery insulating member of the embodiment of the present invention has a melt flow rate (measured at temperature: 315°C, load: 2160 g, according to JIS K7210) of 10 to 80 g/10 minutes. It is preferable. More preferably 12 to 60 g/10 minutes, more preferably 12 to 50 g/10 minutes. Furthermore, 15 to 50 g/10 minutes is preferable, and 25 to 50 g/10 minutes is more preferable. If the melt flow rate is less than 10 g/10 minutes, the fluidity of the resin composition will be low and insufficient filling will occur during injection molding of thin-walled battery insulating members, which is not preferable. If the melt flow rate exceeds 80 g/10 minutes, burrs will occur significantly during injection molding, leading to a decrease in molding processability, which is not preferable.

In the molecular weight distribution obtained from gel permeation chromatography (GPC) measurement of the resin composition, the PPS resin composition constituting the battery insulating member of the embodiment of the present invention has an elution rate corresponding to a molecular weight of 750,000 in terms of polystyrene. The proportion of components detected earlier than the elution time (hereinafter sometimes referred to as component (X)) is 0.4 to 8.5%, and the components detected later than the elution time corresponding to the molecular weight of 750,000 in terms of polystyrene. (hereinafter sometimes referred to as "component (Y)") preferably has a weight average molecular weight of 50,000 to 95,000. By setting the proportion of component (X) and the weight average molecular weight of component (Y) within the above ranges, it is possible to achieve excellent toughness and melt viscosity suitable for molding thin-walled battery insulating members. This is preferable because it leads to a balance between work and work. The proportion of component (X) is preferably 0.5 to 8.0%, more preferably 0.5 to 7.5%. The weight average molecular weight of component (Y) is preferably 60,000 to 90,000, more preferably 65,000 to 85,000. If the proportion of component (X) exceeds 8.5%, the reaction between the PPS resin and the contained components other than the PPS resin will be excessive, resulting in a marked increase in melt viscosity, leading to a decrease in moldability. If it is less than 0.4%, it may be difficult to develop the desired toughness, or it may lead to the occurrence of burrs during molding or mold staining due to low molecular weight components. When the weight average molecular weight of component (Y) is less than 50,000, it means that the molecular weight of the PPS resin in the PPS resin composition is too small, and it is difficult to express the desired toughness, and when it exceeds 95,000, the PPS resin composition Since the molecular weight of the PPS resin inside is too large, it means that the melt viscosity is high, which leads to a decrease in moldability.

Here, the "proportion of components detected earlier than the elution time corresponding to a molecular weight of 750,000" refers to components having a molecular weight of 750,000 or more in terms of polystyrene when the total area of the GPC elution curve is taken as 100%. It is the proportion of the corresponding area area.

From the viewpoint of moldability, the PPS resin composition constituting the battery insulating member of the embodiment of the present invention should have a weight change of 0.5% by weight or less before and after heating and melting at 320°C for 120 minutes. It is preferably 0.3% by weight or less, and even more preferably 0.25% by weight or less. If the weight change exceeds 0.5% by weight, it is not preferable because it leads to mold staining, resulting in a decrease in molding processability and a decrease in electrolyte resistance. Here, the weight change before and after heating and melting the PPS resin composition at 320° C. for 120 minutes was defined as the amount of gas generated. In order to obtain a PPS resin composition with a gas generation amount in the above range, for example, in the post-treatment step of the PPS manufacturing method, it is necessary to wash the PPS resin with an organic solvent or to perform a slight oxidative crosslinking treatment. preferable. Another preferred method is for the PPS resin composition to contain as little thermoplastic elastomer as possible.

The PPS resin composition constituting the battery insulating member of the embodiment of the present invention preferably has an ash content of 1.0% by weight or less, more preferably 0.8% by weight when incinerated at 550°C. The content is preferably 0.5% by weight or less. An ash content of more than 1.0% by weight means that the metal content of the PPS resin composition is high. A high metal content may cause a decrease in toughness, electrolyte resistance, and moldability. In order to obtain a PPS resin composition having an ash content in the above range, it is preferable to avoid adding compounds with a high metal content such as inorganic metal salts as much as possible.

The ash content here is determined by precisely weighing 5 g of the PPS resin composition into a crucible that has been air-fired at 550°C in advance, placing it in an electric furnace at 550°C for 24 hours to incinerate it, and then accurately weighing the amount of ash remaining in the crucible. , and the sample amount before ashing.

The PPS resin composition constituting the battery insulating member according to the embodiment of the present invention has good electrolyte resistance and moldability when the proportion of (a) PPS resin in the resin composition is 95% by weight or more. The content is preferably 97% by weight or more, and even more preferably 98% by weight or more.

(8) Insulating member for batteries The insulating member for batteries composed of the PPS resin composition of the embodiment of the present invention refers to an insulating member for primary or secondary batteries, and is a pair of insulating members in primary or secondary batteries. Used to prevent internal short circuits between terminals. Furthermore, with the recent increase in the capacity of batteries and the rise in temperature in the usage environment, there is an increasing risk of deterioration in battery performance and safety in the event that constituent components of insulating members leak into the electrolyte. Therefore, unlike insulating members for general electrical components, insulating members for batteries are required to have excellent electrolyte resistance in addition to insulation, particularly in high-temperature environments. In response to such technological trends, the battery insulating member composed of the PPS resin composition of the present invention has excellent toughness, electrolyte resistance, heat resistance, and moldability, so it is particularly suitable for high capacity applications. Suitable for primary or secondary batteries.

Primary or secondary batteries include primary batteries such as alkaline manganese dry batteries, galvanic batteries, nickel-based primary batteries, lithium batteries, manganese dry batteries, mercury batteries, all solid-state batteries, lead acid batteries, lithium/air batteries, and lithium ion batteries. Secondary batteries, lithium ion polymer secondary batteries, lithium iron phosphate batteries, lithium-sulfur batteries, nickel-cadmium storage batteries, nickel-hydrogen rechargeable batteries, nickel-lithium batteries, nickel-zinc batteries, all-solid-state batteries, etc. Examples include secondary batteries.

Examples of insulating members for batteries include insulating plates, gaskets, terminal holders, cases, insulating rings, and insulating tubes. A preferable example of the battery insulating member made of the PPS resin composition of the present invention is an insulating plate from the viewpoint of electrolyte resistance in a high-temperature environment.

The present invention will be described in more detail with reference to Examples below, but the present invention is not limited thereto.

In Examples and Comparative Examples, (a) PPS resin, (b) polyethylene, (c) thermoplastic elastomer, (d) amorphous resin with a glass transition temperature of 150°C or higher, and (e) other additives as follows. I used something.

[(a) PPS resin (a-1, 2, 3)]
a-1: Linear PPS resin Weight average molecular weight: 70000, carboxyl group weight: 33 μmol/g, melting point: 280°C
a-2: Crosslinked PPS resin, weight average molecular weight: 49000, carboxyl group weight: 12 μmol/g, melting point: 280°C
a-3: Linear PPS resin Weight average molecular weight: 20000, carboxyl group weight: 50 μmol/g, melting point: 280°C
[(b) Polyethylene (b-1)]
b-1: Polyethylene (manufactured by Prime Polymer, PE7000FP)
[(c) Thermoplastic elastomer (c-1)]
c-1: Ethylene-glycidyl methacrylate copolymer (olefin resin manufactured by Sumitomo Chemical Co., Ltd., Bond First E, melting point 103 ° C., MFR: 3 g / 10 minutes (190 ° C., 21.2 N load)), reactive functional group amount: 12% by weight
[(d) Amorphous resin (d-1, 2) with a glass transition temperature of 150°C or higher]
d-1: Polyether sulfone resin (manufactured by Sumitomo Chemical Co., Ltd., Sumika Excel SE4800G), glass transition temperature: 225°C
d-2: Polyetherimide resin (Sabic, ULTEM1000), glass transition temperature: 217°C
[(e) Other additives (e-1, e-2, e-3, e-4, e-5)]
e-1: γ-isocyanatepropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBE-9007N).
e-2: γ-Aminopropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBE-903)
e-3: 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-303)
e-4: Calcium phosphinate (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.)
e-5: Sodium phosphinate monohydrate (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.)

In the following examples, material properties were evaluated by the following method.

[Tensile test]
An ISO527-2-1A dumbbell test piece was molded using an injection molding machine manufactured by Sumitomo Heavy Industries (SE75DUZ-C250) at a resin temperature of 310°C and a mold temperature of 150°C. The tensile strength and tensile elongation at break of the obtained test piece were measured in accordance with ISO527-1 and 2 under conditions of a distance between fulcrums of 114 mm, a tensile speed of 5 mm/min, a temperature of 23° C., and a relative humidity of 50%.

[GPC measurement]
The weight average molecular weight of the PPS resin, the proportion of the component (X) detected earlier than the elution time corresponding to the polystyrene equivalent molecular weight 750,000 of the PPS resin composition, and the component (X) detected later than the elution time corresponding to the molecular weight 750,000. The weight average molecular weight of Y) was calculated in terms of polystyrene using gel permeation chromatography (GPC). The GPC measurement conditions are shown below.
Equipment: SSC-7110 (Senshu Science)
Column name: Shodex UT806M x 2
Eluent: 1-chloronaphthalene Detector: Differential refractive index detector Column temperature: 210°C
Pre constant temperature bath temperature: 250℃
Pump constant temperature bath temperature: 50℃
Detector temperature: 210℃
Flow rate: 1.0mL/min
Sample injection amount: 300 μL (slurry form: approximately 0.2% by weight).

[Carboxyl group weight of PPS resin]
The carboxyl group content of the PPS resin was calculated using a Fourier transform infrared spectrometer (hereinafter abbreviated as FT-IR).

First, benzoic acid was measured as a standard substance by FT-IR, and the absorption intensity (b1) of the peak at 3066 cm ^-1 , which is the absorption of the C-H bond of the benzene ring, and the peak at 1704 cm ^-1 , which is the absorption of the carboxyl group, were measured. The absorption intensity (c1) was read and the amount of carboxyl groups (U1) per benzene ring unit, (U1)=(c1)/[(b1)/5], was determined. Next, the PPS resin was melt-pressed at 320° C. for 1 minute and then rapidly cooled, and the resulting amorphous film was subjected to FT-IR measurement. Read the absorption intensity (b2) at 3066 cm ^-1 and the absorption intensity (c2) at 1704 cm ^-1 , and calculate the amount of carboxyl groups (U2) per benzene ring unit, (U2) = (c2) / [(b2) / 4]. I asked for it. The carboxyl group content per 1 g of PPS resin was calculated from the following formula.
Carboxyl group amount (μmol/g) of PPS resin = (U2)/(U1)/108.161×1000000.

[Cyclic PPS content in PPS resin]
The cyclic PPS content in the PPS resin was calculated by the following method using high performance liquid chromatography (HPLC).

About 10 mg of PPS resin was dissolved in about 5 g of 1-chloronaphthalene at 250°C. A precipitate formed upon cooling to room temperature. The 1-chloronaphthalene insoluble component was filtered using a membrane filter with a pore size of 0.45 μm to obtain the 1-chloronaphthalene soluble component. The amount of cyclic PPS was determined by HPLC measurement of the obtained soluble component. The HPLC measurement conditions are shown below.
Equipment: Shimadzu Corporation LC-10Avp series Column: Mightysil RP-18 GP150-4.6 (5 μm)
Detector: Photodiode array detector (UV=270 nm).

[Weight change (gas generation amount) before and after heating and melting]
10 g of the PPS resin composition was accurately weighed into an aluminum cup that had been previously heat-treated at 330°C for 3 hours, and heated in a hot air dryer at 320°C for 2 hours. The weight change rate was calculated from the weight of the PPS resin composition before and after heating and melting, and was taken as the amount of gas generated.

[Ash content]
5 g of the PPS resin composition was accurately weighed into a crucible that had been air-fired at 550°C in advance, and the mixture was placed in an electric furnace at 550°C for 24 hours to be incinerated. The amount of ash remaining in the crucible was precisely weighed, and the ratio to the amount of the sample before ashing was defined as the ash content (% by weight).

[Melt flow rate (MFR)]
Using a melt indexer manufactured by Toyo Seiki Co., Ltd., the MFR of the PPS resin composition was measured at a measurement temperature of 315° C. and a load of 2160 g in accordance with JIS K7210.

[Mold stain resistance]
The molded product shown in Figure 1 (molded product size: length: 55 mm, width: 20 mm, thickness: 2 mm, gate size: width: 1.5 mm, thickness: 1 mm, gas vent part: maximum length: 20 mm, width: 10 mm, Injection was performed using a gas evaluation mold with a depth of 5 μm) at a cylinder temperature of 320°C, a mold temperature of 130°C, an injection speed of 100 mm/s, and a filling time of 0.4 seconds for each resin composition. Continuous molding was performed with the pressure set within 50 to 80 MPa, and the mold contamination status at the mold gas vent part was visually observed every 10 shots (molding machine used: "SE75DUZ-C250" manufactured by Sumitomo Heavy Industries). . If the number of shots until mold staining is 100 or more, it can be said to be at a practically usable level, but the larger the number of shots, the better the mold staining resistance, which is preferable. Those with 150 shots or more were rated ◎, those with 100 shots or more were rated ○, those with 50 shots or more were rated △, and those with less than 50 shots were rated ×.

[Electrolyte resistance under high temperature environment]
A test piece with a length of 10 mm, a width of 10 mm, and a thickness of 2 mm was cut out from the molded product obtained in the evaluation of mold stain resistance, and after vacuum drying at room temperature overnight, its weight was accurately weighed. The cut out test piece was placed in a pressure container, 20 g of diethyl carbonate was added thereto, and the container was sealed. After heating in a hot air dryer at 100° C. for 24 hours and cooling to room temperature, the test piece was taken out from the pressure container and vacuum-dried overnight at room temperature. The weight of the test piece was measured, and the rate of change in weight (% by weight) with respect to the initial weight was calculated. The smaller the rate of change in weight, the better the electrolyte resistance, which means that it is possible to prevent deterioration of the electrolyte during actual use, leading to the maintenance of battery characteristics, and the ability to maintain insulation as an insulating material for batteries. do. Those with a weight change rate of 0.2% by weight or less were rated as ○, those with a weight change rate of 0.5% by weight or less were rated as △, and those with a weight change rate of more than 0.5% by weight were rated as ×.

[Examples 1 to 7, 10 to 14, Comparative Examples 1 to 8]
(a) PPS resin, (b) polyethylene, (c) thermoplastic elastomer, (d) amorphous resin with a glass transition temperature of 150°C or higher, and (e) other additives in the proportions shown in Tables 1 and 2. After dry blending, using a TEX30α type twin screw extruder (30 mmφ, L/D = 45) manufactured by Japan Steel Works, equipped with a vacuum vent, the screw arrangement was performed at three kneading sections, and the ratio of the kneading section to the total length of the screw was adjusted. 30%, the cylinder temperature was set at 320° C., and the screw rotation speed was set at 300 rpm for melt-kneading. The melt-kneading method under these conditions is referred to as A. Thereafter, it was pelletized using a strand cutter. The obtained pellets were dried at 130° C. overnight and then used for measurement of gas generation amount, ash content, GPC, and MFR. In addition, the obtained pellets were subjected to injection molding, and mold stain resistance and electrolyte resistance under high temperature environments were evaluated, and the obtained test pieces were subjected to a tensile test. The results were as shown in Tables 1 and 2.

[Example 8, 9]
Melt-kneading, pelletizing, and various characteristic evaluations were carried out in the same manner as in Example 1, except that the screw rotation speed was set at 500 rpm for melt-kneading. The melt-kneading method under these conditions is designated as B. The results were as shown in Table 1.

The results of the above example and comparative example will be compared and explained.

In Examples 1 to 14, excellent toughness and moldability were exhibited by using a PPS resin composition using a linear (a) PPS resin with a cyclic PPS content within a specific range. Since it has excellent mold stain resistance, which is one of molding processability, the electrolyte resistance under high temperature environment was good. Examples 2, 3, 5, and 7 in which phosphorus oxoacid metal salt was added had a tendency to decrease in MFR and increase in viscosity.

On the other hand, Comparative Example 1 using only the linear (a) PPS resin showed low toughness with a tensile elongation at break of 12%. Similarly, Comparative Example 6 had excellent mold stain resistance and good electrolyte resistance under high-temperature environments, but the tensile elongation at break was as low as 11%.

In addition, in Comparative Examples 2 to 4 and 8, since (a) PPS resin with a high cyclic PPS content was used, the amount of gas generated from the PPS resin composition was large, resulting in poor mold fouling resistance and poor electrolysis resistance in high-temperature environments. The result was that the liquid property was low. The toughness was also insufficient. In particular, in Comparative Example 4 in which (c) thermoplastic elastomer was blended, the amount of gas generated was large and the mold staining property was significantly reduced. Therefore, the electrolyte resistance was low in a high-temperature environment.

(e) Comparative Example 5, in which a large amount of phosphorus oxoacid metal salt was blended, had a high ash content and decreased tensile elongation at break.

(e) Comparative Example 7, in which 10 parts by weight of an organic silane compound was blended, had a significant increase in viscosity and could not be molded by injection molding.

1. Molded product for evaluation of mold stain resistance 2. Gate

Claims (8)

An insulating member for a battery, wherein the insulating member is made of a resin composition containing (a) polyphenylene sulfide resin, the proportion of (a) polyphenylene sulfide resin in the resin composition is 89% by weight or more, and the above-mentioned ( a) The content of cyclic polyphenylene sulfide in the polyphenylene sulfide resin is 0.01 to 1.0% by weight, and in a tensile test (ISO527-1, 2) of a test piece obtained by injection molding the resin composition. , a battery insulating member having a tensile elongation at break of 15% or more. The insulating member for a battery according to claim 1, wherein the resin composition has a weight change of 0.5% by weight or less before and after being heated and melted at 320° C. for 120 minutes. 3. The insulating member for a battery according to claim 1, wherein the resin composition contains (b) polyethylene, and the content of (b) polyethylene is 100% of the polyphenylene sulfide resin of (a). An insulating member for a battery having a content of 0.01 to 5.0 parts by weight. The insulating member for a battery according to any one of claims 1 to 3, wherein the resin composition contains (c) a thermoplastic elastomer, and the content of (c) the thermoplastic elastomer is the same as the content of (a). An insulating member for a battery that is less than 1 part by weight based on 100 parts by weight of polyphenylene sulfide resin. The insulating member for a battery according to any one of claims 1 to 4, wherein the resin composition has a melt flow rate (a value measured according to JIS K7210 at a temperature of 315°C and a load of 2160 g). An insulating member for batteries that has a weight of 10 to 80 g/10 minutes. The insulating member for a battery according to any one of claims 1 to 5, wherein the resin composition contains (d) an amorphous resin having a glass transition temperature of 150° C. or higher; An insulating member for a battery, wherein the content of the amorphous resin having a temperature of 150° C. or higher is 0.1 to 11 parts by weight based on 100 parts by weight of the polyphenylene sulfide resin (a). 7. The insulating member for a battery according to claim 6, wherein the (d) amorphous resin having a glass transition temperature of 150° C. or higher is selected from polyethersulfone, polyetherimide, polyphenylene oxide, polyphenylene sulfone, polysulfone, and polycarbonate. At least one insulating member for a battery. The insulating member for a battery according to any one of claims 1 to 7, wherein the ash content when the resin composition is incinerated at 550° C. is 1.0% by weight or less. .

Images