JP5755980B2 - Method for producing imide-modified elastomer - Google Patents

Description

  The present invention relates to a method for producing an imide-modified elastomer.

  A urethane prepolymer having isocyanate groups at both molecular ends obtained from diisocyanate and polyol, as a method for producing a novel imide-modified elastomer having a soft and low elastic modulus and having high strength and high heat resistance, A chain is extended by a urea bond with a diamine compound, and a polyurethaneamic acid (PUA) solution is obtained by reaction with tetracarboxylic dianhydride. After centrifugal molding, this is subjected to a ring-closing reaction (dehydration condensation reaction) by heat treatment. Thus, a production method for synthesizing an imide-modified elastomer which is a block copolymer having an imide unit introduced into a urea bond portion is known (Patent Document 1).

JP 2008-101195 A

  However, in the above production method, in order to obtain a PUA solution, it is necessary to dissolve a prepolymerized urethane prepolymer in an organic solvent such as N-methyl-2-pyrrolidone (NMP). In this case, since 3 to 5 times the amount of the solvent of the polymer is used, there is a problem that the production efficiency at the time of production is low, the cost is increased, and the influence on the environment is concerned. Furthermore, since it is necessary to remove the solvent after the reaction, there is a problem that the reaction process is long and the cost increases in this respect as well.

  Further, the imide-modified elastomer obtained by the above production method has a problem that the degree of coloring is strong and unsuitable for coloring applications. Further, the imide-modified elastomer obtained by the above production method has a problem that the solvent resistance is not sufficient.

  In the above production method, a PUA solution is obtained and subjected to heat treatment after centrifugal molding. On the other hand, when bulk polymerization is performed without using a solvent, the reaction does not proceed. Become a body. Therefore, it was necessary to mold the PUA after increasing the viscosity by clay for a long time (about 12 hours at about 100 ° C.). In addition, there is a problem that aggregates that are insoluble in the solvent remain in the resulting imide-modified elastomer and the quality of the product is impaired. In this way, it is not simply a matter of performing bulk polymerization without using a solvent.

  Therefore, the object of the present invention is to obtain an imide-modified elastomer with reduced coloring and improved solvent resistance, high production efficiency during production, environmental considerations, a short reaction process, and cost reduction. Another object is to provide a method for producing an imide-modified elastomer.

  Therefore, as a result of intensive studies by the present inventors to solve the above-mentioned problems, the average particle size of the fine particles containing tetracarboxylic dianhydride is set to 10 μm or less when tetracarboxylic dianhydride is added. Thus, it was found that aggregates do not occur even when bulk polymerization is performed without using a solvent, and that the resulting PUA has a high viscosity and is clay-like, so that it can be molded without prolonged heat treatment. Completed.

That is, the present invention
Urethane prepolymer (c) represented by the following formula (c), diamine compound (d) represented by the following formula (d), and tetracarboxylic dianhydride (f) represented by the following formula (f) ) In the absence of a solvent and polymerized by heating, and the solid of the diamine compound (d) and tetracarboxylic dianhydride (f) is pulverized to have an average particle size of 10 μm A second step of producing a mixture containing the fine particles as the following fine particles,
Only including, it performs a second step after the first step, and,
After the second step, a polyurethane amic acid synthesis step further comprising a third step of mixing and polymerizing the mixture containing the fine particles under heating , and the polyurethane amic acid obtained in the polyurethane amic acid synthesis step Including a polyurethane amic acid cyclization step in which a cyclization reaction is caused by heat treatment,
There is provided a method for producing an imide-modified elastomer characterized by obtaining an imide-modified elastomer (I) represented by the following formula (I).
[Wherein, R ₁ represents a divalent organic group containing an aromatic ring or an aliphatic ring. R ₂ represents a divalent organic group having a molecular weight of 100 to 10,000. R ₃ represents a divalent organic group containing an aromatic ring, an aliphatic ring or an aliphatic chain. R ₄ represents a tetravalent organic group containing 4 or more carbon atoms. n shows the integer of 1-100. ]
[Wherein R ₁ , R ₂ , R ₃ , R ₄ and n are the same as above. m shows the integer of 5-200. ]

Furthermore, the method for producing the imide-modified elastomer includes a diisocyanate (a) represented by the following formula (a) and a polyol (b represented by the following formula (b), as shown in the following reaction process formula (A). And a urethane prepolymer synthesis step (A) to obtain a urethane prepolymer (c) represented by the following formula (c), which is obtained by the urethane prepolymer synthesis step (A). It is preferable to use the urethane prepolymer (c) in the first step.
[Wherein R ₁ , R ₂ and n are the same as above. ]

  According to the method for producing an imide-modified elastomer of the present invention, since it is not necessary to use a solvent, there is little influence on the environment, production efficiency at the time of production increases, and cost can be reduced. Further, there is no need to remove the solvent or heat treatment for a long time before molding, and the reaction process can be shortened, so that the cost can also be reduced in this respect. Furthermore, an imide-modified elastomer with reduced coloring and improved solvent resistance is obtained.

It is the analysis result of IR spectrum which shows the result of the FT-IR test of the imide modified elastomer obtained by the manufacturing method of the imide modified elastomer of this invention. It is a graph which shows the result of the tensile test of the imide modified elastomer obtained by the manufacturing method of the imide modified elastomer of this invention. It is a graph which shows the result of the dynamic viscoelasticity test of the imide modified elastomer obtained by the manufacturing method of the imide modified elastomer of this invention. 2 is a photomicrograph showing monomer fine particles mixed in a mortar in Example 1. FIG. 4 is a photomicrograph showing an aggregate containing a monomer in Comparative Example 1.

  Below, each process of a polyurethane amic acid synthesis process and a polyurethane amic acid cyclization process is demonstrated in detail.

[1. First step of the polyurethane amic acid synthesis step]
The first step is a urethane prepolymer (c) represented by the above formula (c), a diamine compound (d) represented by the above formula (d), and a tetracarboxylic acid represented by the above formula (f). The acid dianhydride (f) is not particularly limited as long as it is a step of mixing and polymerizing under heating in the absence of a solvent.

(1-1. Mixing method)
Although it does not specifically limit as a mixing method, First, it is preferable to mix a urethane prepolymer (c) and a diamine compound (d), and then add and mix tetracarboxylic dianhydride (f). .

  During the mixing, it is preferable to mix the diamine compound (d) and the tetracarboxylic dianhydride (f) while crushing them. When mixing while crushing, it is conceivable that the average particle size of the solid of tetracarboxylic dianhydride (f) is, for example, 30 μm or less, but crushing so that it is 20 μm or less. It is preferable to crush so as to be 15 μm or less.

  Although it does not specifically limit as conditions for mixing, It is preferable to mix using a kneader. A high shear mixer is preferably used as the kneader. In particular, when the urethane prepolymer (c) and the diamine compound (d) are first mixed and then the tetracarboxylic dianhydride (f) is added and mixed, the tetracarboxylic dianhydride (f ) Is preferably mixed using a kneader, more preferably a high shear mixer. The mixing condition when using a kneader is, for example, about 5 to 200 rpm, and preferably about 10 to 100 rpm.

  The conditions such as the temperature at the time of mixing are not particularly limited, but may be stirred for about 1 to 5 hours at 25 to 150 ° C., preferably 50 to 100 ° C. in an inert gas atmosphere such as nitrogen gas or argon gas. Good.

(1-2. Mixing ratio)
The mixing ratio of the urethane prepolymer (c), the diamine compound (d), and the tetracarboxylic dianhydride (f) is not particularly limited. However, it is preferable to mix the diamine compound (d) with the urethane prepolymer (c) at a ratio of NCO / NH ₂ (molar ratio) of about 0.9 to 1.1, 0.95 to 1 It is more preferable to mix at a ratio of about .05. Moreover, with respect to the urethane prepolymer (c), the tetracarboxylic dianhydride (f) has a mixing ratio (mol) of diamine compound (d): tetracarboxylic dianhydride (f) = 1: 2. It is preferable to mix in the ratio which becomes the range of 1: 2.02. Thereby, an imide unit can be reliably introduced into the urea bond portion.

  Next, each of urethane prepolymer (c), diamine compound (d), and tetracarboxylic dianhydride (f) will be described.

(1-3. Urethane prepolymer (c))
The urethane prepolymer (c) is not particularly limited as long as it is a urethane prepolymer (c) represented by the formula (c), but the urethane prepolymer (c) obtained by the reaction represented by the following reaction process formula (A) ) Is preferable. Specifically, the diisocyanate (a) represented by the formula (a) and the polyol (b) represented by the formula (b) are mixed and reacted to obtain a urethane pre-form represented by the formula (c). Polymer (c) is obtained.

[Reaction process formula (A)]
[Wherein, R ₁ , R ₂ and n are the same as defined above. ]

  In the reaction process formula (A), a urethane prepolymer (c) having isocyanate groups at both molecular ends is obtained from the diisocyanate (a) and the polyol (b). When this urethane prepolymer (c) is used as an elastomer component, the elastic modulus of the rubber-like region (near room temperature) becomes low and can be made more elastic, and the weight average molecular weight of this urethane prepolymer (c) is By controlling, it is possible to introduce two imide units continuous in the main chain at a desired ratio while controlling the distribution thereof.

  The diisocyanate (a) is not particularly limited. For example, 2,4-tolylene diisocyanate (TDI), 2,6-tolylene diisocyanate (TDI), 4,4′-diphenylmethane diisocyanate (MDI), polymeric MDI ( Cr.MDI), dianisidine diisocyanate (DADL), diphenyl ether diisocyanate (PEDI), pitylene diisocyanate (TODI), naphthalene diisocyanate (NDI), hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPDI), lysine diisocyanate methyl ester (LDI) ), Metaxylylene diisocyanate (MXDI), 2,2,4-trimethylhexamethylene diisocyanate (TMDI), 2,4,4-trime Ruhexamethylene diisocyanate (TMDI), dimer acid diisocyanate (DDI), isopropylidenebis (4-cyclohexylisocyanate) (IPCI), cyclohexylmethane diisocyanate (hydrogenated MDI), methylcyclohexane diisocyanate (hydrogenated TDI), TDI dimer ( TT) and the like, but it is preferable to use one distilled under reduced pressure. You may use these 1 type or in mixture of 2 or more types.

  The polyol (b) is not particularly limited. For example, polyether polyol such as polypropylene glycol (PPG), polyoxytetramethylene glycol (PTMG), polymer polyol, etc .; adipate polyol (condensed polyester polyol), polycaprolactone polyol Polyester polyol such as polycarbonate polyol (PCD); polybutadiene polyol; acrylic polyol and the like. You may use these 1 type or in mixture of 2 or more types.

  The polyol (b) is preferably used after drying under reduced pressure under conditions of 70 to 90 ° C., 1 to 5 mmHg, and 30 minutes to 30 hours. The weight average molecular weight of the polyol (b) is 100 to 10,000, preferably 300 to 5,000. The weight average molecular weight is a value obtained by measuring the polyol (b) by gel permeation chromatography (GPC) and converting the obtained measurement value to polystyrene.

  The reaction is performed by mixing the diisocyanate (a) and polyol (b) exemplified above at a predetermined ratio, and then at room temperature to 100 ° C. for about 1 hour to 5 hours in an inert gas atmosphere such as nitrogen gas or argon gas. What is necessary is just to make it react. The mixing ratio (mole) of diisocyanate (a) and polyol (b) is preferably in the range of diisocyanate (a): polyol (b) = 1.01: 1 to 2: 1. Thereby, the weight average molecular weight of the urethane prepolymer (c) obtained can be made into the predetermined value demonstrated below.

  That is, the weight average molecular weight of the urethane prepolymer (c) obtained is 300 to 50,000, preferably 500 to 45,000. When the weight average molecular weight of the urethane prepolymer (c) is controlled within this range and the imide unit is introduced at a desired ratio, it is a flexible rubber-like material having a low elastic modulus and has high strength and high heat resistance. An imide-modified elastomer (I) can be obtained.

More specifically, when the weight average molecular weight of the urethane prepolymer (c) is in the predetermined range, the imide fraction (imide component content) of the imide-modified elastomer (I) is 5 to 45% by weight, preferably 5 It can be made into 40 weight%. The imide fraction means the ratio of the imide component in the imide-modified elastomer. When the imide fraction is within the predetermined range, the distribution and ratio of two consecutive imide units introduced into the main chain are optimized, and as a result, the imide-modified elastomer (I) has a flexible low elastic modulus. A rubber-like material having high strength and high heat resistance. On the other hand, when the imide fraction is lower than 5% by weight, the strength and heat resistance may be lowered, and when it exceeds 45% by weight, the flexibility may be lowered. The imide fraction is a value calculated from the amounts of raw materials, that is, diisocyanate (a), polyol (b), diamine compound (d) described later, and tetracarboxylic dianhydride (f), and more specifically. Is a value calculated from the following formula (α).
Imide fraction (%) = [(W _{a ′} + W _c + W _d ) / W _total ] × 100 (α)
W _total : W _a + W _b + W _c + W _d
W _a : Diisocyanate charge (mole) × Diisocyanate formula quantity W _b : Polyol charge quantity (mol) × Polyol formula quantity W _c : Diamine compound charge (mol) × Diamine compound formula quantity W _d : Tetracarboxylic acid dianhydride Charge amount (mole) × tetracarboxylic dianhydride formula amount Wa _′ : [diisocyanate charge amount (mol) −polyol charge amount (mol)] × diisocyanate formula amount

  Moreover, harder imide-modified elastomer (I) can be obtained, so that the weight average molecular weight of urethane prepolymer (c) is small in the said range. On the other hand, when the molecular weight is less than 300, the imide-modified elastomer (I) becomes too hard and the flexibility may be lowered. On the other hand, if it is larger than 50,000, the imide-modified elastomer (I) becomes too soft, and the strength and heat resistance may be lowered. The weight average molecular weight is a value obtained by measuring the urethane prepolymer (c) by GPC and converting the obtained measurement value into polystyrene.

(1-4. Diamine Compound (d))
Although it does not specifically limit as a diamine compound (d), For example, 1, 4- diaminobenzene (alias: p-phenylenediamine, abbreviation: PPD), 1, 3- diaminobenzene (alias: m-phenylenediamine, abbreviation: MPD), 2,4-diaminotoluene (alias: 2,4-toluenediamine, abbreviation: 2,4-TDA), 4,4′-diaminodiphenylmethane (aka: 4,4′-methylenedianiline, abbreviation: MDA) ), 4,4′-diaminodiphenyl ether (alias: 4,4′-oxydianiline, abbreviation: ODA, DPE), 3,4′-diaminodiphenyl ether (alias: 3,4′-oxydianiline, abbreviation: 3) , 4'-DPE), 3,3'-dimethyl-4,4'-diaminobiphenyl (also known as o-tolidine, abbreviation: TB), 2,2'-dimethyl-4,4'- Aminobiphenyl (alias: m-tolidine, abbreviation: m-TB), 2,2′-bis (trifluoromethyl) -4,4′-diaminobiphenyl (abbreviation: TFMB), 3,7-diamino-dimethyldibenzothiophene -5,5-dioxide (alias: o-tolidine sulfone, abbreviation: TSN), 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 4,4'-bis (4-aminophenyl) sulfide (alias : 4,4'-thiodianiline, abbreviation: ASD), 4,4'-diaminodiphenylsulfone (also known as 4,4'-sulfonyldianiline, abbreviation: ASN), 4,4'-diaminobenzanilide (abbreviation: DABA) ), 1, n-bis (4-aminophenoxy) alkane (n = 3,4,5, abbreviation: DAnMG), 1,3-bis (4-aminophenoxy) -2,2-dimethylpropane (abbreviation: DANPG), 1,2-bis [2- (4-aminophenoxy) ethoxy] ethane (abbreviation: DA3EG), 9,9-bis (4-aminophenyl) fluorene (abbreviation) : FDA), 5 (6) -amino-1- (4-aminomethyl) -1,3,3-trimethylindane, 1,4-bis (4-aminophenoxy) benzene (abbreviation: TPE-Q), 1 , 3-bis (4-aminophenoxy) benzene (alias: resorcinoxydianiline, abbreviation: TPE-R), 1,3-bis (3-aminophenoxy) benzene (abbreviation: APB), 4,4′-bis (4-aminophenoxy) biphenyl (abbreviation: BAPB), 4,4′-bis (3-aminophenoxy) biphenyl, 2,2-bis (4-aminophenoxyphenyl) propane (abbreviation) : BAPP), bis [4- (4-aminophenoxy) phenyl] sulfone (abbreviation: BAPS), bis [4- (3-aminophenoxy) phenyl] sulfone (abbreviation: BAPS-M), 2,2-bis [ 4- (4-aminophenoxy) phenyl] hexafluoropropane (abbreviation: HFBAPP), 3,3′-dicarboxy-4,4′-diaminodiphenylmethane (abbreviation: MBAA), 4,6-dihydroxy-1,3- Phenylenediamine (also known as 4,6-diaminoresorcin), 3,3'-dihydroxy-4,4'-diaminobiphenyl (also known as 3,3'-dihydroxybenzidine, abbreviated as HAB), 3,3 ', 4 Aromatic diamine compounds having 6 to 27 carbon atoms such as 4′-tetraaminobiphenyl (also known as 3,3′-diaminobenzidine, abbreviation: TAB); 1,6 Hexamethylenediamine (HMDA), 1,8-octamethylenediamine (OMDA), 1,9-nonamethylenediamine, 1,12-dodecamethylenediamine (DMDA), 1-amino-3-aminomethyl-3,5, C6-C24 aliphatic or alicyclic diamine compounds such as 5-trimethylcyclohexane (also known as isophoronediamine), 4,4'-dicyclohexylmethanediamine, cyclohexanediamine; 1,3-bis (3-aminopropyl) Examples include silicone-based diamine compounds such as -1,1,3,3-tetramethyldisiloxane, and these may be used alone or in combination. In particular, when 1,6-hexamethylenediamine (HMDA) is used, an imide-modified elastomer (I) having excellent strength can be obtained. When 1,4-bis (4-aminophenoxy) benzene (TPE-Q) or 1,3-bis (4-aminophenoxy) benzene (TPE-R) is used, an imide-modified elastomer (I) having excellent solvent resistance Can be obtained.

(1-5. Tetracarboxylic dianhydride (f))
The tetracarboxylic dianhydride (f) is not particularly limited. For example, pyromellitic anhydride (PMDA), oxydiphthalic dianhydride (ODPA), benzophenone-3,4,3 ′, 4′-tetracarboxylic Acid dianhydride (BTDA), biphenyl-3,4,3 ′, 4′-tetracarboxylic dianhydride (BPDA), diphenylsulfone-3,4,3 ′, 4′-tetracarboxylic dianhydride ( DSDA), 4,4 ′-(2,2-hexafluoroisopropylidene) diphthalic dianhydride (6FDA), m (p) -terphenyl-3,4,3 ′, 4′-tetracarboxylic dianhydride , Cyclobutane-1,2,3,4-tetracarboxylic dianhydride, 1-carboxymethyl-2,3,5-cyclopentanetricarboxylic acid-2,6: 3,5-dianhydride, and the like. . Among them, pyromellitic anhydride (PMDA), oxydiphthalic dianhydride (ODPA), benzophenone-3,4,3 ′, 4′-tetracarboxylic dianhydride from the viewpoints of heat resistance, solvent resistance and processability (BTDA) is preferred. You may use these 1 type or in mixture of 2 or more types.

[2. Second step of the polyurethane amic acid synthesis step]
If the second step is a step of pulverizing the solid of the diamine compound (d) and the tetracarboxylic dianhydride (f) to produce a mixture containing the fine particles as fine particles having an average particle size of 10 μm or less. Although not particularly limited, the average particle diameter of the fine particles is more preferably 10 μm or less, and further preferably 5 μm or less.

  The second step may be performed before or after the first step, or together with the first step, but is preferably performed after the first step. When the second step is performed after the first step and the third step is further performed, there is an advantage that it becomes easier to mix the reactants.

  The method for producing an imide-modified elastomer according to the present invention includes the second step, thereby reducing solvent-insoluble aggregates found in the imide-modified elastomer (I) when the reaction is carried out without using a solvent. Therefore, the quality of the product is not impaired.

  The method of pulverizing the solid of the diamine compound (d) and the tetracarboxylic dianhydride (f) to obtain fine particles having an average particle diameter of 10 μm or less is not particularly limited. Specifically, for example, it is conceivable to use a mortar, three rolls, etc., and it is more preferable to use a mortar.

[3. Third step of the polyurethane amic acid synthesis step]
The third step is not particularly limited as long as it is a step in which the mixture containing the fine particles is further heated and polymerized after the second step. Further, the polyurethane amic acid synthesis step does not necessarily include the third step.

  As described above, when the second step is performed after the first step and the third step is further performed, there is an advantage that it becomes easier to mix the reactants. In the second step, the solid of the diamine compound (d) and the tetracarboxylic dianhydride (f) is pulverized and subjected to a polymerization reaction, so that the unreacted diamine compound (d) and the tetracarboxylic acid dihydrate are obtained. There is also an advantage that the anhydride (f) is greatly reduced.

  Although it does not specifically limit as a mixing method, It is preferable to mix using a kneader. As the kneader, a closed kneader is preferably used, and a small closed kneader is more preferably used. Moreover, it is also preferable to mix continuously using a single screw extruder or a twin screw extruder. The kneader is preferably a kneader having a heating function. Moreover, as mixing conditions in the case of using a kneader, it is about 10-200 rpm, for example, Preferably it is about 20-100 rpm.

  Although it does not specifically limit as temperature at the time of mixing, What is necessary is just to stir in 25-200 degreeC, Preferably it is 50-150 degreeC. The mixing time is not particularly limited, but it is preferable to stop the mixing when the torque increases and becomes maximum and then decreases and becomes stable.

[4. Polyurethane Amic Acid Ring Closing Step]
The polyurethane amic acid ring closing step is not particularly limited as long as it is a step for causing a ring closing reaction by heat-treating the polyurethane amic acid (PUA) obtained in the polyurethane amic acid synthesis step.

  By subjecting PUA to heat treatment, a ring closure reaction (dehydration condensation reaction) occurs, and an imide-modified elastomer (I) represented by the above formula (I) is obtained.

  Although it does not specifically limit as heating conditions in the said heat processing, For example, it is pressure reduction conditions, for example, 150-450 degreeC, Preferably it is 150-250 degreeC, For example, it is about 1 hour-5 hours. Under these conditions, PUA is preferable in that it is more difficult to thermally decompose.

  After molding the polyurethane amic acid (PUA) obtained in the polyurethane amic acid synthesis step, the molded polyurethane amic acid (PUA) may be subjected to the heat treatment or obtained in the polyurethane amic acid synthesis step. The heat treatment may be performed before molding the polyurethane amic acid (PUA). The molding method is not particularly limited. For example, a method of extrusion molding after continuous mixing in a single screw extruder or twin screw extruder, press molding such as a hot plate press, or open roll kneading. Roll kneading is preferred.

Although what kind of shape PUA is made by the molding is not particularly limited, for example, it can be molded into a sheet, film, or plate, and is preferably molded into a sheet.

  As thickness of imide modified elastomer (I) (or PUI) obtained when PUA is shape | molded and made into a sheet form, a film form, or plate shape, about 0.1-10 mm is mentioned, for example.

[5. Chemical reaction in the production method of the present invention]
In the chemical reaction in the production method of the present invention, as shown in the following reaction process formula (D), the urethane prepolymer (c) represented by the following formula (c) first reacts with the diamine compound (d). Then, a polyurethane-urea compound (e) represented by the following formula (e) is obtained, and then the polyurethane-urea compound (e) reacts with the tetracarboxylic dianhydride (f) to give the following formula ( It is considered that an imide-modified elastomer (I) represented by I) is obtained.

[Wherein, R ₁ , R ₂ , R ₃ , R ₄ , n, m are the same as described above. ]

  Hereinafter, regarding the chemical reaction in the present invention, the reaction until the urethane prepolymer (c) and the diamine compound (d) react to produce the polyurethane-urea compound (e), and the polyurethane-urea compound (e) and the tetracarboxylic acid. This will be explained separately from the reaction until the dianhydride (f) reacts to produce the imide-modified elastomer (I).

(5-1. Reaction until polyurethane-urea compound (e) is formed)
As a reaction until the polyurethane-urea compound (e) is generated, as shown in the following reaction process formula (B), the urethane prepolymer (c) is chain-extended with a diamine compound (d) by a urea bond, and the polyurethane-urea Compound (e) is obtained.

[Reaction process formula (B)]
[Wherein, R ₁ , R ₂ , R ₃ , n and m are the same as described above. ]

  The above reaction is presumed to occur mainly in the absence of a solvent during the first step.

(5-2. Reaction until imide-modified elastomer (I) is produced)
As the reaction until the imide-modified elastomer (I) is produced, as shown in the following reaction process formula (C), the polyurethane-urea compound (e) reacts with the tetracarboxylic dianhydride (f), An imide-modified elastomer (I) represented by the following formula (I) is produced. That is, an imide-modified elastomer (I), which is a block copolymer, is obtained by introducing an imide unit into the urea bond portion with tetracarboxylic dianhydride (f). The left end of the polymer chain of the imide-modified elastomer (I) represented by the following formula (I) is usually an NCO group, and the right end is usually an NCO group, NH ₂ group, (CO) ₂ O. One of the groups.

[Reaction process formula (C)]
[Wherein, R ₁ , R ₂ , R ₃ , R ₄ , n, m are the same as described above. ]

  The reaction represented by the reaction process formula (C) is an imidization reaction between the polyurethane-urea compound (e) and the tetracarboxylic dianhydride (f).

  As the imidization reaction, first, the polyurethane-urea compound (e) and the tetracarboxylic dianhydride (f) exemplified above react to react with the polyurethane amic acid represented by the following formula (g) ( PUA) is obtained. The above reaction is presumed to occur mainly in the absence of a solvent during the polyurethane amic acid synthesis step.

  The PUA after the imidization reaction is in the form of clay and already has a sufficient viscosity, so that it can be molded as it is without heat treatment for a long time. As described above, in the case of the conventional bulk polymerization without using a solvent, since the PUA obtained is a viscous body, it was necessary to mold the PUA after heat-treating it into a clay for a long time. . Therefore, according to the method of the present invention, the reaction process is shortened, and the cost is also reduced in this respect. The reason why the PUA after the reaction already has a sufficient viscosity is presumed to be that the efficiency of the reaction has been improved by the uniform mixing in the initial stage.

(5-3. Imide-modified elastomer (I))
The imide-modified elastomer of the present invention is represented by the general formula (I). In the formula, as R ₁ , for example, a divalent aliphatic hydrocarbon group, a divalent aromatic hydrocarbon group, an ether bond (—O—), an ester bond (—C (═O) O -), thioether bond (-S-), amide bond (-C (= O) -NH _2), carbonyl group (-C (= O) -), sulfinyl group (-SO-), or a sulfonyl group (- Examples thereof include a hydrocarbon group in which two or more of these are bonded through or without SO ₂ —).

  The divalent aliphatic hydrocarbon group and the divalent aromatic hydrocarbon group may have a substituent. Examples of the substituent include an alkyl group, an aralkyl group, an aryl group, an alkoxy group, a hydroxyl group, an amino group, a carboxyl group, and a halogen atom. As said alkyl group, C1-C6 alkyl groups, such as a methyl group, an ethyl group, a propyl group, are mentioned, for example. As said aralkyl group, C6-C12 aralkyl groups, such as a benzyl group, a phenylethyl group, a phenylpropyl group, are mentioned, for example. As said aryl group, C6-C20 aryl groups, such as a phenyl group, a tolyl group, a xylyl group, a biphenylyl group, a naphthyl group, an anthryl group, a phenanthryl group, are mentioned, for example. As said alkoxy group, C1-C6 alkoxy groups, such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group, are mentioned, for example. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

  The divalent aliphatic hydrocarbon group and the divalent aromatic hydrocarbon group may have a hetero atom. As said hetero atom, a nitrogen atom, an oxygen atom, a sulfur atom etc. are mentioned, for example.

  Examples of the divalent aliphatic hydrocarbon group include an alkylene group, an alkenylene group, an alkynylene group, an aralkylene group, and the like, and those having an aliphatic ring are preferable. As said bivalent aliphatic hydrocarbon group, a C1-C30 (especially C2-C20) thing is preferable.

  Examples of the divalent aromatic hydrocarbon group include a phenylene group, a biphenylene group, and a naphthylene group. As said bivalent aromatic hydrocarbon group, a C1-C30 (especially C6-C20) thing is preferable.

Further, examples of R ₁ are residues such diisocyanates for use in the synthesis of the urethane prepolymer (c) (a) and the like in accordance with the above-mentioned reaction scheme (A). Among these, 4,4′-diphenylmethane diisocyanate (MDI) or a residue of tolylene diisocyanate is preferable among the diisocyanates (a).

R ₂ represents a divalent organic group having a molecular weight of 100 to 10,000, preferably 300 to 5,000. Examples of the organic group include a saturated or unsaturated linear or branched polyvalent aliphatic hydrocarbon group, a polyvalent alicyclic hydrocarbon group, and a polyvalent aromatic hydrocarbon group. Examples thereof include a chemical group selected from the group, or a hydrocarbon group in which two or more of these are bonded. The hydrocarbon group may have a hetero atom and / or a substituent, and specific examples of the hetero atom and the substituent are the same as those for R ₁ .

  Examples of the saturated or unsaturated linear or branched polyvalent aliphatic hydrocarbon group include an alkylene group, an alkenylene group, an alkanetriyl group, and an alkenetriyl group. Examples of the polyvalent alicyclic hydrocarbon group include 1,2-cyclopentylene group, 1,3-cyclopentylene group, 1,2-cyclohexylene group, 1,3-cyclohexylene group, 1, Cycloalkylene groups such as 4-cyclohexylene group; cycloalkylidene groups such as cyclohexylidene group; norbornane-2,3-diyl group, norbornane-2,5-diyl group, norbornane-2,6-diyl group Valent bridged cyclic hydrocarbon group and the like. Examples of the polyvalent aromatic hydrocarbon group include arylene groups such as a phenylene group such as a 1,2-phenylene group, a 1,3-phenylene group, and a 1,4-phenylene group.

Moreover, as said R < ₂ >, the residue etc. of the polyol (b) used when synthesize | combining a urethane prepolymer (c) according to reaction process formula (A) mentioned above are mentioned. Among these, among the residues of polyol (b), those of polyoxytetramethylene glycol (PTMG) or polypropylene glycol (PPG) are preferred.

R ₃ represents a divalent organic group containing an aromatic ring, an aliphatic ring or an aliphatic chain. Examples of the organic group include a divalent aliphatic hydrocarbon group, a divalent aromatic hydrocarbon group, an ether bond (—O—), an ester bond (—C (═O) O—), and a thioether. Bond (—S—), amide bond (—C (═O) —NH ₂ ), carbonyl group (—C (═O) —), sulfinyl group (—SO—), or sulfonyl group (—SO ₂ —) And a hydrocarbon group in which two or more of these are bonded through or without. The hydrocarbon group may have a hetero atom and / or a substituent, and specific examples of the hetero atom and the substituent are the same as those for R ₁ .

  Examples of the divalent aliphatic hydrocarbon group include an alkylene group, an alkenylene group, an alkynylene group, an aralkylene group, and the like. The divalent aliphatic hydrocarbon group includes those having 1 carbon atom, preferably those having 1 to 30 carbon atoms, and more preferably 6 to 24 carbon atoms. The 1,6-hexamethylene group is particularly preferred because an imide-modified elastomer (I) having excellent strength can be obtained.

  Examples of the divalent aromatic hydrocarbon group include a phenylene group, a biphenylene group, and a naphthylene group. The divalent aromatic hydrocarbon group includes those having 1 carbon atom, preferably those having 1 to 30 carbon atoms, and more preferably 6 to 27 carbon atoms.

  Examples of the hydrocarbon group in which two or more of these are bonded include a methylphenylene group, a methylbiphenylene group, and a diphenyl ether group.

Examples of R ₃ include residues of the diamine compound (d) used when the polyurethane-urea compound (e) is synthesized according to the above-described reaction process formula (B). Specific examples of the residue include, for example, 4,4′-diaminodiphenylmethane, 1,4-bis (4-aminophenoxy) benzene (TPE-Q), among the residues of the diamine compound (d), A residue of 1,3-bis (4-aminophenoxy) benzene (TPE-R) is particularly preferable in that an imide-modified elastomer (I) having excellent solvent resistance can be obtained.

R ₄ represents a tetravalent organic group containing 4 or more carbon atoms, for example, a hydrocarbon group such as a tetravalent aliphatic hydrocarbon group and a tetravalent aromatic hydrocarbon group. And a tetravalent aromatic hydrocarbon group is preferable. The hydrocarbon group may have a hetero atom and / or a substituent, and specific examples of the hetero atom and the substituent are the same as those for R ₁ .

Examples of R ₄ include a residue of tetracarboxylic dianhydride (f) used when synthesizing the imide-modified elastomer (I) according to the reaction process formula (C) described above. Specific examples of the residue include pyromellitic anhydride (PMDA), oxydiphthalic dianhydride (ODPA), benzophenone-3,4,3 ′, 4′-tetracarboxylic dianhydride (BTDA). And the like are preferred.

  Specific examples of the imide-modified elastomer represented by the general formula (I) (hereinafter also referred to as imide-modified elastomer (I)) include an imide-modified elastomer represented by the following formula (1).

[Wherein, n and m are the same as described above. x shows the integer of 5-100. ]

  The imide-modified elastomer (I) obtained by the production method of the present invention is a tetracarboxylic dianhydride obtained by extending a urethane prepolymer having an isocyanate group at both molecular ends obtained from diisocyanate and polyol by a urea bond with a diamine compound. The block copolymer is preferably a block copolymer having an imide unit introduced into the urea bond.

  The imide-modified elastomer (I) obtained by the production method of the present invention is a flexible rubber-like material having a low elastic modulus, not only has high strength and high heat resistance, but also has a high weight average molecular weight, high brightness, Excellent solvent resistance.

Specifically, the storage elastic modulus E ′ at 50 ° C. of the imide-modified elastomer (I) obtained by the production method of the present invention is preferably 5 × 10 ⁶ to 1 × 10 ⁸ Pa. As will be described later, the storage elastic modulus is a value obtained by measurement using a dynamic viscoelasticity measuring apparatus. The imide-modified elastomer (I) having such a flexible low elastic modulus has a glass transition temperature (Tg) of usually −30 to −60 ° C. and a wide temperature range of the rubber-like elastic region. The reason why the imide-modified elastomer (I) is a flexible rubber-like material having a low elastic modulus and has high strength and high heat resistance is presumed as follows. That is, as explained above, the imide-modified elastomer (I) of the present invention can introduce two imide units continuous in the main chain at a desired ratio (imide fraction) while controlling the distribution thereof. Therefore, the aggregation of the hard segment composed of the imide unit becomes uniform and strong. For this reason, the imide-modified elastomer (I) forms a more uniform and strong microphase separation structure, and the glass transition temperature is lowered, so that the temperature range of the rubber-like elastic region is widened. As a result, even a rubber-like material containing polyurethane as an elastomer component and having a soft and low elastic modulus has high strength and high heat resistance.

  The weight average molecular weight of the imide-modified elastomer (I) obtained by the production method of the present invention is 10,000 to 1,000,000, preferably 50,000 to 500,000, more preferably 80,000 to 100,000. There should be. On the other hand, if the weight average molecular weight is less than 10,000, the solvent resistance, strength and heat resistance may be reduced, and if it is greater than 1,000,000, the moldability may be reduced. Absent. The said weight average molecular weight is the value measured by melt | dissolving the polymer after a polyurethane amic acid synthesis process in NMP, and measuring by GPC.

  The reason why the weight average molecular weight is higher than that of the imide-modified elastomer (I) obtained by solution polymerization using a conventional solvent is presumed as follows. That is, after the step of extending the urethane prepolymer (c) with the diamine compound (d) by a urea bond, the urea bond may be cleaved, and the frequency at which the cleaved urea bond is rebound is determined by the concentration of the compound. It is thought that it is decided by. In this regard, in the case of solution polymerization, since the concentration is relatively low, the probability that the cleaved urea bond is recombined is low. On the other hand, in the case of the present invention, since no solvent is used, the concentration is high and the probability that the urea bond is recombined increases, and as a result, it is estimated that a high weight average molecular weight is maintained.

  The brightness of the imide-modified elastomer (I) obtained by the production method of the present invention is 70 to 95, preferably 80 to 95. On the other hand, if the lightness is less than 70, coloring is difficult and applications may be limited. The brightness is a value measured according to JIS Z8729.

  The solvent resistance of the imide-modified elastomer (I) obtained by the production method of the present invention is superior to that of the imide-modified elastomer (I) obtained by solution polymerization using a conventional solvent. As described later, the solvent resistance is evaluated by immersing the imide-modified elastomer (1) sheet in a predetermined solvent and measuring the weight increase before and after the immersion to calculate the swelling rate (%).

  According to the method for producing an imide-modified elastomer of the present invention, it is a rubber-like product having a soft and low elastic modulus, and has high strength, high heat resistance and thermoplasticity, and has a high weight average molecular weight, high brightness, and high coloring. Therefore, an imide-modified elastomer that is stable against solvents can be produced. The imide-modified elastomer is, for example, a gasket, a sheet, a belt, a film, a tube, a hose, a roll gear, a packing material, a soundproof material, a vibration-proof material, a boot, a coating material, a separation film for pervaporation, an optical nonlinear material, an elastic material. It can be used for fibers, piezoelectric elements, actuators, other various automobile parts, industrial machine parts, sporting goods, and the like. Further, since the imide-modified elastomer (I) obtained by the reaction can be subjected to press molding, roll kneading, etc., and can be molded into a sheet, film, or plate, it is particularly useful for gaskets, sheets, belts, etc. However, it is not limited to these applications.

  Hereinafter, although the synthesis example and an Example are given and the imide modified elastomer of this invention is demonstrated in detail, this invention is not limited only to the following synthesis examples and Examples.

[Synthesis example]
(Synthesis of urethane prepolymer (j))
Urethane prepolymer (j) was synthesized based on the following reaction process formula. Specifically, 4,4′-diphenylmethane diisocyanate (MDI) (h) [manufactured by Nippon Polyurethane Industry Co., Ltd.] was distilled under reduced pressure. Also, polyoxytetramethylene glycol (PTMG) (i) [trade name “PTMG1000” manufactured by Hodogaya Chemical Co., Ltd., weight average molecular weight: 1,000] was dried under reduced pressure at 80 ° C., 2-3 mmHg, 24 hours. .

[Wherein, n and x are the same as defined above. ]

  Next, 69.54 g of PTMG (i) was added to a 500 ml separable flask, degassed under vacuum conditions at 80 ° C. for 1 hour, and then 30.46 g of the above MDI (h) was further added. The mixture was stirred at 80 ° C. for 2 hours and a half at 180 rpm to obtain a urethane prepolymer (j) having an isocyanate group at both molecular ends.

[Example 1]
From the urethane prepolymer (j) obtained above, an imide-modified elastomer (1) was synthesized based on the following reaction process formula. Specifically, 100 g of urethane prepolymer (j) was put into a high shear mixer (trade name “TK Hibismix”, manufactured by Primix Co., Ltd.), and 4,4′-diamino while stirring at 80 ° C. Diphenylmethane (MDA) (k) (10.34 g) was added, and the mixture was further stirred for 1 hour. Subsequently, 22.75 g of pyromellitic anhydride (PMDA) (m) was added and stirred for another hour. The product was taken out and mixed in a mortar until it was dispersed to such an extent that the monomer fine particles could not be visually confirmed (average particle diameter was about 5 μm). After mixing, the product is taken out, put into a small hermetic kneader (trade name “Lab Plast Mill”, manufactured by Toyo Seiki Seisakusho Co., Ltd.), mixed at 100 ° C. and 50 rpm, the torque increases and then decreases. When stable, mixing was stopped and the product was removed. The obtained product was charged into a mold and subjected to hot plate pressing at 180 ° C., followed by heat treatment in a 200 ° C. oven for 2 hours to obtain a sheet-like imide-modified elastomer (1) having a thickness of 0.5 mm.

  As a result of mixing the monomer fine particles in a mortar, it was confirmed using a microscope (trade name “Digital Microscope VHX-900”, manufactured by Keyence Corporation) that the average particle size was about 5 μm. The photograph is shown in FIG.

[Wherein, n, m and x are the same as above. ]

[Comparative Example 1]
As a result of not mixing in the mortar, the same experiment as in Example 1 was performed, except that the average particle size of the aggregate containing the monomer was about 300 μm, and a sheet-like imide-modified elastomer having a thickness of 0.5 mm. (1) was obtained.

  It was confirmed using a microscope (trade name “Digital Microscope VHX-900”, manufactured by Keyence Corporation) that the average particle size of the aggregate containing the monomer was about 300 μm. The photograph is shown in FIG.

[Comparative Example 2]
Reaction was carried out by solution polymerization as follows to obtain a sheet-like imide-modified elastomer (1) having a thickness of 0.5 mm.

First, as shown in the following reaction process formula, the urethane prepolymer (j) obtained by the same method as in Example 1 and 4,4′-diaminodiphenylmethane (MDA) (k) are reacted to form the following formula (l The polyurethane-urea compound (l) represented by this was obtained. Specifically, first, 100 g of urethane prepolymer (j) was dissolved in 200 ml of dehydrated N-methyl-2-pyrrolidone (NMP), and 4,4′-diaminodiphenylmethane (MDA) (k) 10 .34 g dissolved in 50 ml of dehydrated NMP were respectively added to a 500 ml four-necked separable flask and stirred at room temperature (23 ° C.) for 24 hours under an argon atmosphere to obtain a polyurethane-urea compound (l) Solution was obtained.
[Wherein, n and x are the same as above. m ′ represents an integer of 2 to 100. ]

Next, as in the following reaction process formula, the polyurethane-urea compound (1) obtained above was reacted with pyromellitic anhydride (PMDA) (m) to obtain a sheet of an imide-modified elastomer (1). . Specifically, first, 22.75 g of pyromellitic anhydride (PMDA) (m) was added to the polyurethane-urea compound (l) solution obtained above, and the mixture was stirred at 150 ° C. for 2 hours in an argon gas atmosphere. Thus, a polyurethane amic acid (PUA) solution was obtained. Next, the PUA solution was poured into a centrifugal molding machine and subjected to centrifugal molding at 150 ° C. and 1,000 rpm for 1 hour to obtain a PUA sheet. This PUA sheet was subjected to heat treatment (dehydration condensation reaction) at 200 ° C. for 2 hours in a vacuum desiccator to obtain a sheet-like imide-modified elastomer (1) having a thickness of 0.5 mm.
[Wherein, n, m and x are the same as above. ]

[FT-IR test]
IR spectrum was measured about the obtained imide modified elastomer (1). For the measurement of the IR spectrum, an ATR jig (manufactured by PIKE) was used with a spectrometer (trade name “FTS-3000”, manufactured by VALIAN). Further, the IR spectrum was measured by ATR method measurement by pressing a sample, and the number of integration was 32 times. The result is shown in FIG. The horizontal axis of the graph of FIG. 1 indicates the number of wavelengths (cm ⁻¹ ), and the vertical axis indicates the absorbance (Abs.).

From the results shown in FIG. 1, in either case of Example 1 and Comparative Example 2, 1780 cm ^-1, absorption derived from the imide ring in 1720 cm ^-1 and 1380 cm ^-1 were observed, these imide-modified elastomers (1 ) Sheets were shown to have the same chemical structure.

[Tensile test]
The obtained imide-modified elastomer (1) sheet was punched out with a No. 3 dumbbell, and was autographed (trade name “AGS-G”, Shimadzu Corporation) in accordance with JIS K6251 under conditions of a gap between marked lines of 20 mm and a tensile speed of 500 mm / min. The stress and the elongation were measured respectively. The result is shown in FIG. In the graph of FIG. 2, the vertical axis represents stress (MPa) and the horizontal axis represents elongation (%).

  The results shown in FIG. 2 indicate that there is no difference in the stress and flexibility of the imide-modified elastomer (1) sheet in any of Example 1 and Comparative Example 2 (solution polymerization).

[Dynamic viscoelasticity test]
The obtained imide-modified elastomer (1) sheet was subjected to a dynamic viscoelasticity test. The dynamic viscoelasticity test is performed using a dynamic viscoelasticity measuring device (trade name “DMS 6100”, manufactured by Seiko Instruments Inc.) in a temperature rising process of 20 Hz, 5 ° C./min, −100 to 400 ° C., and stored. The elastic modulus (E ′) and loss tangent (tan δ) were measured. The result is shown in FIG. In the graph, the left vertical axis represents storage elastic modulus E ′ (Pa), the left vertical axis represents loss tangent tan δ, and the horizontal axis represents temperature (° C.).

  The results shown in FIG. 3 show that there is no difference in the dynamic viscoelastic behavior with respect to temperature of the imide-modified elastomer (1) sheet in any of Example 1 and Comparative Example 2 (solution polymerization). It was.

[Brightness evaluation of imide-modified elastomer (1) sheet]
The imide-modified elastomer (1) sheet obtained in Example 1 has a light yellow color, whereas the imide-modified elastomer (1) sheet obtained in Comparative Example 2 has a dark brown color. The visual difference was clear. In order to objectively evaluate such a difference in lightness, the lightness of the imide-modified elastomer (1) sheet was measured according to JIS Z8729, and the results are shown in the “lightness” column of Table 1 below.

  From the results shown in Table 1, it was objectively shown that the imide-modified elastomer (1) sheet obtained in Example 1 had excellent brightness.

[Evaluation of solvent resistance of imide-modified elastomer (1) sheet]
The imide-modified elastomer (1) sheet was immersed in N-methyl-2-pyrrolidone (NMP) at room temperature (23 ° C.) for 96 hours, and the weight increase before and after the immersion of the imide-modified elastomer (1) sheet was measured. More specifically, a test piece having a width of 2.0 cm and a length of 3.0 cm was cut out from the imide-modified elastomer (1) sheet, this test piece was immersed in a solvent under the above conditions, and the weight before and after immersion was expressed by the following formula ( The swelling ratio (%) was calculated by applying to β) and used as an index of solvent resistance.
Swell ratio (%) = [(S2-S1) / S1] × 100 (β)
S1: Weight of the test piece before immersion S2: Weight of the test piece after immersion

  From the results shown in Table 1, it was shown that the imide-modified elastomer (1) sheet obtained in Example 1 has excellent solvent resistance.

[Evaluation of weight average molecular weight of imide-modified elastomer (1) sheet]
The weight average molecular weight of the imide-modified elastomer (1) sheet was measured, and the result is shown in the column of “molecular weight (Mw)” in Table 1 below.

  From the results shown in Table 1, it was shown that the imide-modified elastomer (1) sheet obtained in Example 1 had a high weight average molecular weight.

  According to the method for producing an imide-modified elastomer of the present invention, it is not necessary to use a solvent, so the production efficiency at the time of production is increased, the cost can be reduced because there is no need to remove the solvent, and further, coloring is reduced, Since an imide-modified elastomer having improved solvent resistance is obtained, it is particularly useful as a method for producing a rubber molded product such as a gasket.

Claims (2)

Urethane prepolymer (c) represented by the following formula (c), diamine compound (d) represented by the following formula (d), and tetracarboxylic dianhydride (f) represented by the following formula (f) ) In the absence of a solvent and polymerized by heating, and the solid of the diamine compound (d) and tetracarboxylic dianhydride (f) is pulverized to have an average particle size of 10 μm A second step of producing a mixture containing the fine particles as the following fine particles,
Only including, it performs a second step after the first step, and,
After the second step, a polyurethane amic acid synthesis step further comprising a third step of mixing and polymerizing the mixture containing the fine particles under heating , and the polyurethane amic acid obtained in the polyurethane amic acid synthesis step Including a polyurethane amic acid cyclization step in which a cyclization reaction is caused by heat treatment,
The manufacturing method of the imide modified elastomer characterized by obtaining the imide modified elastomer (I) represented by a following formula (I).
[Wherein, R ₁ represents a divalent organic group containing an aromatic ring or an aliphatic ring. R ₂ represents a divalent organic group having a molecular weight of 100 to 10,000. R ₃ represents a divalent organic group containing an aromatic ring, an aliphatic ring or an aliphatic chain. R ₄ represents a tetravalent organic group containing 4 or more carbon atoms. n shows the integer of 1-100. ]
[Wherein R ₁ , R ₂ , R ₃ , R ₄ and n are the same as above. m shows the integer of 5-200. ] Furthermore, according to the following reaction process formula (A), the reaction is carried out by mixing the diisocyanate (a) represented by the following formula (a) and the polyol (b) represented by the following formula (b). A urethane prepolymer synthesis step (A) for obtaining a urethane prepolymer (c) represented by the formula (c),
The method for producing an imide-modified elastomer according to claim 1, wherein the urethane prepolymer (c) obtained by the urethane prepolymer synthesis step (A) is used in the first step.
[Wherein, R ₁ represents a divalent organic group containing an aromatic ring or an aliphatic ring. R ₂ represents a divalent organic group having a molecular weight of 100 to 10,000. n shows the integer of 1-100. ]