JP2002003810A - Flame-retardant polyester resin for adhesive and the adhesive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a flame-retardant polyester resin for adhesives, which is more excellent in adhesive property and hydrolysis resistance than conventional flame-retardant polyester resins, and the adhesive. SOLUTION: The flame-retardant polyester resin for adhesives comprises >=0.5 wt.% of phosphorus existing in a molecular chain, an acid component containing 40 mol% or more of an aromatic dicarboxylic acid, and a glycol component containing 60 mol% or more of a glycol having a carbon number of 4 or more; and the adhesive comprises this polyester resin. Especially, the flame-retardant polyester resin for the adhesives is characterized in that the resin is produced by copolymerizing a phosphorus-containing carboxylic acid or the esterifies product represented by formula 1 or formula 2 and has a glass transition temperature of -15 deg.C or higher and lower than 40 deg.C; and the adhesive comprises the 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 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 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 a resin in order to achieve a high flame retardancy, the hydrolyzability decreases along 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, in the present invention, the phosphorus component contained in the molecular chain is 0.5% by weight or more, the aromatic dicarboxylic acid is 40% by mole or more of the acid component, and the glycol having 4 or more carbon atoms is the glycol component. 60 mol%
The polyester resin for an adhesive and the adhesive contained therein.

Preferably, it is obtained by copolymerizing a phosphorus-containing carboxylic acid represented by the general formula 1 or a phosphorus-containing carboxylic acid represented by the general formula 2 or an ester thereof,
More preferably, the glass transition temperature is −15 ° C. or more and 40 ° C.
Less than a polyester resin for an adhesive and its adhesive.

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

[0013]

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

[0014]

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.
The above is preferably 0.7% by weight or more, more preferably 1.0% by weight or more, and most preferably 2.0% by weight. If the phosphorus atom content is less than 0.5% by weight, the flame retardancy is low, and it may be difficult to use as a flame retardant adhesive.
As a method for introducing a phosphorus atom into these resins, a general method is used.
Alternatively, a method of 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.

[0015]

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

[0016]

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 ⁵ is a hydrocarbon group such as methyl, ethyl, propyl, phenyl.

R ³ , R ⁴ , R ⁶ and R ⁷ are a hydrogen atom, methyl,
Ethyl, propyl, butyl, phenyl, benzyl, 2-
It is a hydrocarbon group such as hydroxyethyl, 2-hydroxypropyl, 3-hydroxypropyl, 4-hydroxypropyl, 2-hydroxyethyloxyethyl, or a hydroxy-substituted hydrocarbon group.

Further, among the acid components of the polyester of the present invention, it is preferable that the aromatic dicarboxylic acid is copolymerized in an amount of 40 mol% or more, preferably 55 mol% or more, more preferably 70 mol% or more. 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 components of the polyester resin include 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 necessary to contain at least 60 mol% of a glycol having 4 or more carbon atoms in the glycol component of the polyester. More preferably, it is 70 mol%, and still more preferably 80 mol%. 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. For example, when an aliphatic dicarboxylic acid or an alicyclic dicarboxylic acid having an acidity higher than that of an aromatic dicarboxylic acid is copolymerized as an acid component in an amount of 60 mol% or more, the hydrolyzability of an ester group is improved, which is not preferable.

It is not preferable that 40 mol% or more of a glycol having 3 or less carbon atoms is copolymerized as a glycol component, because the ester group concentration increases and the hydrolysis resistance decreases.

The glycol component having 4 or more carbon atoms is 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
Ethylene oxide adduct and propylene oxide adduct of toluene A, ethylene oxide adduct and propylene oxide adduct of hydrogenated bisphenol A, 1,
9-nonanediol, 2-methyloctanediol,
1,10-decanediol, 2-butyl-2-ethyl-
Examples include 1,3-propanediol, tricyclodecane dimethanol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and the like.

As glycols having 3 or less carbon atoms, ethylene glycol, 1,2-propylene glycol, 1,3-
Propanediol and the like can be copolymerized within a range of less than 40 mol%.

The glass transition temperature of the polyester adhesive is-
15 ° C or higher and lower than 40 ° C, preferably -10 ° C or higher and 35 ° C or lower.
C., and more preferably -5.degree. C. or more and less than 30.degree. 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 13,000 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.

When the resin of the present invention is used in combination with a flame retardant, the flame retardant effect of the phosphorus-containing polyester resin can be further enhanced. 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 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, and fibers such as polyester and nylon. It can be used as an impregnating resin. Further, the present invention can be applied to a flame-retardant plastic based on polyester or the like as a structural material.

[0030]

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: Resin is dissolved in chloroform-d
^It was quantified by ^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 sulfuric acid 3 ml, perchloric acid 0.5 ml and nitric acid 3.5 ml are measured. , 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: The number average molecular weight was determined by gel permeation chromatography using tetrahydrofuran as a solvent in terms of polystyrene. 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 an outflow cooler, the compound represented by the 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 was a pale yellow solid having a glass transition temperature of 75 ° C. and a number average molecular weight of 2,200.

In another reactor, 852 parts of terephthalic acid, 825 parts of isophthalic acid, 1166 parts of sebacic acid, 30 parts of trimellitic anhydride, 866 parts of 2-methyl-1,3-propanediol, 1704 parts of 1,6-hexanediol And 5.46 parts of tetrabutyl titanate were charged into an autoclave, and an esterification reaction was carried out at 180 to 240 ° C. for 2 hours. Next, after the completion of the esterification reaction, 2940 parts of a polyester oligomer (Formula 4) was added, and the mixture was stirred for 10 minutes.
While the temperature of the reaction system was raised from 240 ° C. to 275 ° 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 65 minutes to obtain a copolymerized polyester.

As a result of NMR analysis, the copolymerized polyester was found to contain 23 mol% of a terephthalic acid component, 19 mol% of an isophthalic acid component, 28 mol% of a sebacic acid component, and a component derived from the formula (5).
Is represented as dicarboxylic acid for convenience. ) 29 mol%, trimellitic acid component 1 mol%, ethylene glycol component 8
Mol%, 2-methyl-1,3-propanediol component 2
It was a pale yellow resin having a composition of 7 mol% and a 1,6-hexanediol component of 65 mol%, a number average molecular weight of 25,000, a phosphorus content of 3.5 wt%, and a glass transition temperature of 6 ° C.

Embedded image

<Synthesis Examples 2 to 6 of Resins Copolymerized with Phosphorus,
Comparative Synthetic Examples 1 to 5> 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 copolymerization is small. Comparative Synthesis Examples 4 and 5 are outside the scope of the present invention because they do not contain an aromatic dicarboxylic acid in an amount of 40 mol% or more.

[0039]

[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)

[0040]

[Table 2]

Example 1 Flame Retardancy: Limiting 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 is laminated on a 50 μm biaxially stretched PP film so as to have a thickness of 30 μm. The film was placed in a constant temperature / humidity oven at 40 ° C. and 90% with the adhesive side up, and allowed to stand for 100 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 5> 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 5 are inferior in any of oxygen index (flame retardancy), adhesiveness, and hydrolysis resistance.

[0044]

[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

[0045]

[Table 4]

[0046]

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.

Continued on front page F-term (reference) 4J029 AA03 AB01 AC02 AD01 AD07 AE13 BA02 BA03 BA04 BA05 BA09 BA10 BF25 CA02 CA06 CB03A CB05A CB06A CB10A CC05A CC06A CD04 CH03 DC05 HA01 HB01 HB03A 4J040 ED04 MA02 LA01 NA11 NA15 NA20

Claims (4)

[Claims] (1) a phosphorous atom contained in a molecular chain is 0.5 wt.
% Or more, and the aromatic dicarboxylic acid is 40% of the acid component.
A flame-retardant polyester resin for an adhesive, comprising at least 60 mol% of a glycol having at least 4 mol% and at least 4 carbon atoms. 2. The flame-retardant polyester resin for an adhesive according to claim 1, which is obtained by copolymerizing a phosphorus-containing carboxylic acid represented by the following general formula 1 or 2 and / or an ester compound thereof. 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 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. An adhesive using the flame-retardant polyester resin according to claim 1.