JP2002003587A - Flame-retarded polyester resin for adhesive and adhesive thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flame-retarded polyester resin affording a flame-retardant polyester adhesive having better adhesion, resistance to hydrolysis or the like compared to conventional flame-retarded polyester adhesives. SOLUTION: This flame-retarded polyester resin for adhesive is obtained by co-polymerizing a phosphorus containing carboxylic acid or its ester compound having 0.5 wt.% or more phosphorus atom in the molecule and containing less than 40 mol% of ethylene glycol, preferably expressed by formula 1 or formula 2, further preferably having a glass transition temperature of -15 deg.C or higher and lower than 40 deg.C. This adhesive is made by using the flame- retardant polyester resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phosphorus-containing polyester adhesive having excellent adhesiveness and flame retardancy, and exhibiting excellent durable adhesiveness because a decrease in molecular weight can be suppressed even after long-term use. is there.

[0002]

2. Description of the Related Art In recent years, flame retardant materials have been demanded in various fields. For example, in the case of OA equipment and home electric appliances, it is necessary to prevent a fire from occurring even if a polymer material is ignited due to abnormal heating due to malfunction of parts. Later rapid self-digestion has become important. Therefore, in order to develop a more advanced flame-retardant material, a flame-retardant technology is required for an adhesive such as a flame-retardant molding material.

In the conventional flame retardant adhesives, it is difficult to introduce a halogen atom into the skeleton or to use a halogen-based flame retardant and antimony trioxide in combination, as seen in JP-A-52-29830. Combustion prescriptions are well known.

[0004] However, the problem of dioxins generated during waste disposal is accelerating the recent efforts to address global environmental problems, and the use of halogen-based flame retardants has been regulated. For example, the movement of eco-labels in Europe.

[0005] Generally, as a technique relating to a non-halogen, low harmful, low smoke generating flame retardant system, for example, a method of adding a phosphorus flame retardant can be mentioned. Since these materials are provided with flame retardancy by adding a phosphorus-containing additive such as a phosphoric acid ester to a resin in a large amount at the time of materialization, the adhesiveness, heat resistance and various application properties are deteriorated. Not only do
The flame retardant itself will bleed out.

Accordingly, various methods have been proposed for imparting flame retardancy to the polyester resin itself in a halogen-free manner. Among them, a flame retarding technique by copolymerization of a phosphorus compound is disclosed in JP-A-53-128195. Gazette, JP 63
It is proposed in, for example, -150352.

Hitherto, among many polyester-based adhesives that have been used for various applications, hydrolysis may occur depending on the application and the use environment, and the molecular weight of the resin may be reduced. As a result, the properties of various resins are impaired, such as a decrease in cohesive force and a decrease in adhesive strength. Further, in order to impart flame retardancy to the polyester adhesive, a problem has arisen that copolymerization of a phosphorus-containing dicarboxylic acid compound or the like further deteriorates the hydrolysis resistance of the resin.
For example, when the hydrolyzability of the phosphorus-containing polyester adhesive used in JP-A-10-46474 was examined, a decrease in the molecular weight was recognized, and the durability adhesiveness for long-term use was insufficient.

Further, when a large amount of a phosphorus-containing dicarboxylic acid or the like is copolymerized in order to increase the phosphorus content in the resin in order to achieve a high flame retardancy, the hydrolyzability is further reduced together with the phosphorus content.

As described above, it is very difficult to sufficiently suppress the hydrolyzability by the conventional technology, and therefore, a phosphorus-containing compound that maintains high adhesive strength even when used for a long time and realizes high flame retardancy. Copolyester adhesives have not yet been proposed.

[0010]

The present invention relates to a polyester adhesive used for automobile parts, electric appliances, films, and textiles, and exhibits excellent flame retardancy without using halogens which are environmentally problematic. An object of the present invention is to provide a polyester adhesive which is excellent not only in performance but also in performance such as adhesion and hydrolysis resistance.

[0011]

Means for Solving the Problems The present inventors have conducted intensive studies to obtain a polyester adhesive which is non-halogen and excellent in flame retardancy, hydrolysis resistance, adhesiveness and mechanical properties. Reached. That is, the phosphorus atom contained in the molecular chain is 0.5 wt% or more, and the content of ethylene glycol is less than 40 mol%, and preferably the phosphorus-containing dicarboxylic acid represented by the general formula 1 or the general formula 2
A flame-retardant polyester resin for an adhesive obtained by copolymerizing with a phosphorus-containing carboxylic acid or an esterified product thereof, and more preferably having a glass transition temperature of −15 ° C. or more and less than 40 ° C. And an adhesive comprising:

Embedded image R ^1, R ^2: a hydrogen atom or a hydrocarbon group R ^3, R ^4,: a hydrogen atom, a hydrocarbon group or a hydroxy group-substituted hydrocarbon group l, m: 0 to 4 integer

[0012]

Embedded image R ⁵ : hydrogen atom or hydrocarbon group R ⁶ , R ⁷ : hydrogen atom, hydrocarbon group or hydroxy-substituted hydrocarbon group

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION In the polyester adhesive used in the present invention, a monomer having a phosphorus atom is introduced by copolymerization or modification in order to impart halogen-free flame retardancy, and a phosphorus atom is contained in a molecular chain. Is required. The amount of phosphorus atoms contained is 0.5 wt% based on the weight of the resin.
As described above, the content is preferably 0.7% by weight or more, more preferably 1.0% by weight, and most preferably 2.0% by weight or more. If the phosphorus atom content is less than 0.5 wt%, the flame retardancy is low, and it is difficult to use as a flame retardant adhesive. As a method for introducing a phosphorus atom into these resins, a general method is used, and among them, in particular, the following general formula 1 or
A method using a phosphorus-containing carboxylic acid represented by the general formula 2 or an esterified product thereof as a copolymer component is preferable from the viewpoint of economy and the like. In addition to the compounds represented by the above formula, alkyl-bis (3-hydroxypropyl) phosphine oxide, alkyl-bis (3-hydroxycarbonylethyl) phosphine oxide, etc. (where alkyl is methyl, ethyl, propyl, butyl, etc.) Etc.) are also preferred.

Embedded image R ^1, R ^2: a hydrogen atom or a hydrocarbon group R ^3, R ^4,: a hydrogen atom, a hydrocarbon group or a hydroxy group-substituted hydrocarbon group l, m: 0 to 4 integer

[0014]

Embedded image R ⁵ : hydrogen atom or hydrocarbon group R ⁶ , R ⁷ : hydrogen atom, hydrocarbon group or hydroxy-substituted hydrocarbon group

Specific examples of R ¹ , R ² and R ⁵ are a hydrogen atom and a hydrocarbon group such as methyl, ethyl, propyl and phenyl. R ¹ and R ² may be the same or different. R ³ , R ⁴ , R ⁶ and R ⁷ are a hydrogen atom,
Methyl, ethyl, propyl, butyl, phenyl, benzyl, 2-hydroxyethyl, 2-hydroxypropyl,
3-hydroxypropyl, 4-hydroxybutyl, 2-
And a hydrocarbon group such as hydroxyethyloxyethyl or a hydroxy-substituted hydrocarbon group.

Further, among the acid components of the polyester of the present invention, the aromatic dicarboxylic acid is preferably copolymerized in an amount of at least 40 mol%, preferably at least 55 mol%, more preferably at least 70 mol%. This is because increasing the aromatic ring concentration further improves the flame retardant effect. This is because the polyester resin is an aromatic condensed resin, particularly an oxygen-containing condensed resin, which itself has a carbonized film forming ability, expresses self-digestibility, and is further copolymerized with a phosphorus-containing compound. Therefore, this is phosphoric acid in the solid phase during combustion,
This is because polyphosphoric acid is formed and acts as a dehydrating agent, thereby promoting formation of a carbonized film.
Further, by using an aromatic dicarboxylic acid, hydrolysis resistance is improved, and stability under high temperature and high humidity is improved.

The dibasic acid component of the polyester resin includes terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid,
6-naphthalenedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, 2,2′-diphenyldicarboxylic acid,
Aromatic dibasic acids such as 4,4′-diphenyl ether dicarboxylic acid, adipic acid, azelaic acid, sebacic acid,
Aliphatic or alicyclic dibasic acids such as 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 4-methyl-1,2-cyclohexanedicarboxylic acid, and dimer acid Copolymerization can be performed within the above range.

Further, it is essential that the content of ethylene glycol in the glycol component of the polyester is less than 40 mol%. Preferably it is less than 30 mol%, more preferably less than 20 mol%. Further, it is preferable to contain 60 mol% or more of a glycol having 4 or more carbon atoms. This is because copolymerization of a phosphorus-containing dicarboxylic acid compound to impart flame retardancy to the polyester adhesive has caused a problem that the hydrolysis resistance of the resin is further deteriorated. In general, it is considered that the phosphorus bond causes hydrolysis and phosphoric acid is generated, thereby promoting the hydrolysis of the polyester main skeleton. When the content of ethylene glycol is at least 40 mol%, the hydrolysis resistance will decrease due to an increase in the ester group concentration. In addition, when an aliphatic dicarboxylic acid or an alicyclic dicarboxylic acid having an acidity higher than that of an aromatic dicarboxylic acid is copolymerized in an amount of 60 mol% or more as an acid component, the hydrolyzability of an ester group is undesirably improved.

As the glycol component, ethylene glycol
1,2-propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol,
1,2-butanediol, 1,3-butanediol,
1,4-butanediol, 1,5-pentaneddiol,
1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 2,2,4-trimethyl-1,5-pentanediol , Cyclohexanedimethanol, neopentyl hydroxypivalate, bisphenol A ethylene oxide and propylene oxide adducts, hydrogenated bisphenol A ethylene oxide and propylene oxide adducts, 1,9 -Nonanediol, 2-methyloctanediol, 1,10-decanediol, 2-butyl-2-ethyl-1,3-propanediol, tricyclodecanedimethanol and the like. As the polyether polyol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol and the like can be copolymerized within the above range.

The glass transition temperature of the polyester resin used in the present invention is from -15 ° C to less than 40 ° C, preferably from -10 ° C to less than 35 ° C, more preferably from -5 ° C to less than 30 ° C. When the glass transition temperature is lower than -15 ° C, the elastic modulus of the adhesive at a high temperature decreases, and the adhesive strength becomes insufficient. For example, when used as an adhesive for automobile parts and home electric appliances, the adhesive strength in a high-temperature environment in summer decreases, and it becomes difficult to sufficiently adhere the parts to each other. On the other hand, when the glass transition temperature is -15 ° C. or lower, blocking of the polyester resin becomes severe, and handling of a substrate such as a film becomes difficult after applying an adhesive. On the other hand, when the glass transition temperature exceeds 40 ° C., the elastic modulus near room temperature increases, and the resin itself is too hard to exhibit adhesiveness to an adherend.

The number average molecular weight of the resin of the present invention is preferably 8000 or more. More preferably, it is 10,000 or more, more preferably 15,000 or more. Number average molecular weight is 800
If it is less than 0, the mechanical strength is insufficient, and various application properties such as adhesiveness are impaired.

The flame retardant effect of the phosphorus-containing polyester resin can be further enhanced by using the resin of the present invention in combination with a flame retardant. For example, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, triethyl phosphate, cresyl diphenyl phosphate, xylenyl diphenyl phosphate, cresyl bis (2,6-xylenyl) phosphate, 2-ethylhexyl Phosphate, dimethyl methyl phosphate, resorcinol bis (diphenyl) phosphate, bisphenol A bis (diphenyl) phosphate, bisphenol A bis (dicresyl) phosphate, diethyl-N, N-bis (2-hydroxyethyl) aminomethyl phosphate Phosphate amides, organic phosphine oxides, phosphorus-based flame retardants such as red phosphorus, ammonium polyphosphate, phosphazene, cyclophosphazene, triazine, Min cyanurate, succinoguanamine guanamine, ethylene melamine, Toriguanamin, cyanuric acid triazinyl salt, melem, melam, tris (beta-cyanoethyl) isocyanurate, acetoguanamine, guanyl melamine sulfate, melem sulfate,
Nitrogen flame retardant such as melam sulfate, diphenyl sulfone-3
-Metal salt-based flame retardants such as potassium sulfonate, aromatic sulfonimide metal salt, polystyrene sulfonate alkali metal salt, aluminum hydroxide, magnesium hydroxide, dolomite, hydrotalcite, barium hydroxide, basic magnesium carbonate, water Hydrated metal flame retardants such as zirconium oxide and tin oxide, silica, aluminum oxide, iron oxide, titanium oxide, manganese oxide, magnesium oxide, zirconium oxide, zinc oxide, molybdenum oxide,
Cobalt oxide, bismuth oxide, chromium oxide, tin oxide,
Inorganic flame retardants such as antimony oxide, nickel oxide, copper oxide, tungsten oxide, zinc borate, zinc metaborate, barium metaborate, zinc carbonate, magnesium carbonate, calcium carbonate, barium zinc stannate, and silicon-based difficulties such as silicone powder It is a fuel. A higher flame retardant effect can be obtained from the combined effect of the high flame retardancy of the phosphorus compound-containing resin itself and the flame retardant mechanism of the flame retardant.

As the polyester flame-retardant adhesive, a curing agent such as an epoxy resin, an acid anhydride and an isocyanate compound, and a curing catalyst such as a tin-based or amine-based compound can be used, if necessary. In particular, an epoxy resin is very preferable in exhibiting heat resistance.

The polyester adhesive of the present invention can be used for bonding or impregnating various plastic films such as polyimide and polyester, metal foil such as copper, stainless steel and aluminum, epoxy impregnated glass cloth or epoxy impregnated nonwoven fabric, polyester and nylon fiber, and the like. It can be used as a resin for applications. Further, the present invention can be applied to a flame-retardant plastic based on polyester or the like as a structural material.

[0025]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. The measured values described in the examples were measured by the following methods. Composition: The resin was dissolved in deuterated chloroform and quantified by H ¹ -NMR. Glass transition temperature: Measurement sample 10 using a differential scanning calorimeter
mg in an aluminum pan, hold the lid tightly and seal.
The measurement was performed at a heating rate of min.

Phosphorus atom content: (Quantitative determination of phosphorus by wet decomposition / molybdenum blue colorimetry) A sample is weighed in an Erlenmeyer flask according to the phosphorus concentration in the sample, and 3 ml of sulfuric acid, 0.5 ml of perchloric acid and 3.5 ml of nitric acid are used. , And the mixture was gradually decomposed by heating over a half day using an electric heater. When the solution became clear, it was further heated to produce white smoke of sulfuric acid, allowed to cool to room temperature, and transferred to a 50 ml volumetric flask,
5 ml of 2% ammonium molybdate solution and 0.2%
2 ml of a hydrazine sulfate solution was added, and the contents were made up with pure water, and the contents were mixed well. Place the flask in a boiling water bath for 10 minutes to heat and color, then cool to room temperature with water, deaerate with ultrasound, take the solution into an absorption cell 10 mm, and control the blank test solution with a spectrophotometer (wavelength 830 nm). And the absorbance was measured. The phosphorus content was determined from the previously prepared calibration curve, and the P concentration in the sample was calculated. Number average molecular weight: Determined as polystyrene equivalent value by gel permeation chromatography using tetrahydrofuran as a solvent. Hereinafter, the present invention will be specifically illustrated by way of examples. In the examples, “parts” means “parts by weight”.

<Synthesis Example 1 of Resin Copolymerized with Phosphorus> In a reaction vessel equipped with a stirrer, a thermometer, and a cooler for effluent, formula 3 was added.
Of ethylene glycol solution (solid content: 50%) (GHM-1 manufactured by Sanko Co., Ltd.) and 0.6 part of tetrabutyl titanate, and heated to 200 ° C. Next, while the temperature of the reaction system was raised to 250 ° C., the pressure inside the system was gradually reduced to 500 Pa over 60 minutes. Then, a polycondensation reaction was further performed at 130 Pa or lower for 55 minutes to obtain a polyester oligomer formula 4.

Embedded image

Embedded image n is an integer of 2 or more. This oligomer has a glass transition temperature of 7
It was a pale yellow solid having a number average molecular weight of 2200 at 5 ° C. In another reactor, 852 parts of terephthalic acid and 825 of isophthalic acid were added.
Part, sebacic acid 1166 parts, trimellitic anhydride 30
Parts, 866 parts of 2-methyl-1,3-propanediol,
1704 parts of 1,6-hexanediol and 3.28 parts of tetrabutyl titanate were charged into an autoclave,
The esterification reaction was performed at ~ 240 ° C for 2 hours. Next, after the esterification reaction is completed, 2940 parts of a polyester oligomer (Formula 4) is added, and the mixture is stirred for 10 minutes. Then, while the temperature of the reaction system is raised from 240 ° C. to 275 ° C., the inside of the system is gradually depressurized, and The pressure was set to 500 Pa. And
Further, a polycondensation reaction was performed at 130 Pa or less for 65 minutes to obtain a copolymerized polyester. Copolymer polyester is NMR
As a result of analysis, terephthalic acid 23 mol%, isophthalic acid 19
Mole%, sebacic acid 28 mole%, component of formula 5 29 mole%
(Formula 5 is represented as a dicarboxylic acid for convenience), 1 mol% of trimellitic acid, 8 mol% of ethylene glycol, 27 mol% of 2-methyl-1,3-propanediol, and 65 mol% of 1,6-hexanediol. It was a pale yellow resin having a number average molecular weight of 25,000, a phosphorus content of 3.5 wt%, and a glass transition temperature of 6 ° C.

[0028]

Embedded image

<Synthesis Examples 2 to 6 of Resin Copolymerized with Phosphorus,
Comparative Synthetic Examples 1 to 6> In the same manner as in Synthetic Example 1, polyester resins having the compositions shown in Tables 1 and 2 were obtained using the respective raw materials.
Comparative Synthesis Examples 1 to 3 are out of the scope of the present invention because phosphorus is not copolymerized or the copolymerization amount is small. Further, Comparative Synthesis Examples 4 to 6 are outside the scope of the present invention because they contain ethylene glycol in an amount of 40 mol% or more.

[0030]

[Table 1] * 1) TPA: terephthalic acid * 2) IPA: isophthalic acid * 3) NDC: 2,6-naphthalenedicarboxylic acid * 4) DPDA: 4,4'-diphenyldicarboxylic acid * 5) AA: adipic acid * 6) SA : Sebacic acid * 7) DDA: dodecane dicarboxylic acid * 8) Formula 5: dicarboxylic acid represented by formula 5 * 9) TMA: trimellitic anhydride * 10) EG ethylene glycol * 11) 2MG: 2-methyl-1, 3-propanediol * 12) 1,3-PD: 1,3-propanediol * 13) NPG: neopentyl glycol * 14) 1,6-HD: 1,6-hexanediol * 15) ND: 1,9 -Nonanediol * 16) DDO dimer diol (Pripol 2033 manufactured by Unichema) * 17) PTG: polytetramethylene glycol (molecular weight) 000)

[0031]

[Table 2] <Example 1> Flame retardancy: Limit oxygen index according to JIS K7201 oxygen index method
(LOI). This is the minimum oxygen concentration required for the sample to burn. The greater the oxygen index, the higher the flame retardancy. Adhesion: 50% of the polyester adhesive obtained in Synthesis Example 1
The film is laminated on a biaxially stretched PET film having a thickness of 30 μm. The adhesive layers were combined and bonded using a roll laminator manufactured by Tester Sangyo Co., Ltd. The lamination was performed at a temperature of 170 ° C., a pressure of 0.3 mPa, and a speed of 0.5 m /
min. Adhesion strength is made by Toyo Baldwin RT
Using M100, a tensile test was performed in an atmosphere of 25 ° C. and 60 ° C., and T was measured at a tensile speed of 50 mm / min.
The mold peel adhesion was measured. Molecular weight reduction rate: The polyester adhesive obtained in Synthesis Example 1 was coated on a 50 μm biaxially stretched PP film with an adhesive having a thickness of 3
The layers are laminated so as to have a thickness of 0 μm. The film was placed in a constant temperature and humidity oven at 40 ° C. and 90%
Let stand for hours. In order to examine the hydrolysis resistance of the sample subjected to the accelerated test in this way, the adhesive was peeled off from the PP film, the number average molecular weight was measured, and the reduction rate was calculated. (Judgment) ：: Molecular weight reduction rate of less than 5%, ：: Molecular weight reduction rate of 5% or more and less than 10%, ×: Molecular weight reduction rate of 10% or more

<Examples 2 to 6, Comparative Examples 1 to 6> Each of the polyester adhesive samples shown in Tables 1 and 2 was evaluated in the same manner as in Example 1. As can be seen from Table 3, the polyester adhesive of the present invention has excellent flame retardancy, and has excellent performance in hydrolysis resistance and adhesiveness, as compared with the prior art. On the other hand, as seen in Table 4, Comparative Examples 1 to 6 are inferior in any of the oxygen index (flame retardancy), adhesiveness, and hydrolysis resistance.

[0033]

[Table 3] * 1) Stored at 40 ° C. and 90% RH and measured after 100 hours: Molecular weight reduction rate is less than 5%, ：: 5% or more and less than 10%,
×: 10% or more

[0034]

[Table 4]

[0035]

According to the present invention, when it is used as an adhesive or a resin for impregnation, it has excellent adhesiveness even in a high-temperature atmosphere, has high flame retardancy, and has little hydrolysis. A durable adhesive that can be used can be realized.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4H028 AA46 4J029 AA05 AB01 AC01 AD07 AE13 BA03 DC03 DC05 4J040 DD071 GA05 GA26 LA06 LA07 LA08 NA10 NA16 NA19

Claims (4)

[Claims] (1) a phosphorous atom contained in a molecular chain is 0.5 wt.
% And the ethylene glycol content is 40% or more.
A flame-retardant polyester resin for an adhesive, which is less than mol%. 2. The flame-retardant polyester resin for an adhesive according to claim 1, wherein a phosphorus-containing carboxylic acid represented by the general formula 1 or 2 or an ester compound thereof is copolymerized. 3. The flame-retardant polyester resin for an adhesive according to claim 1, wherein the glass transition temperature is from −15 ° C. to less than 40 ° C. 4. A flame-retardant polyester adhesive using the polyester according to claim 1. Embedded image R ¹ , R ² : hydrogen atom or hydrocarbon group R ³ , R ⁴ : hydrogen atom, hydrocarbon group or hydroxy-substituted hydrocarbon group 1, m: integer of 0 to 4 R ⁵ : hydrogen atom or hydrocarbon group R ⁶ , R ⁷ : hydrogen atom, hydrocarbon group or hydroxy-substituted hydrocarbon group