JP6567896B2 - Mold release agent for vulcanized rubber molding - Google Patents

Description

  The present invention relates to a release agent for molding vulcanized rubber.

  Vulcanized rubber is used in automobile parts, railway parts, construction machinery and the like. These vulcanized rubbers can be obtained by putting the rubber composition into a mold or the like, vulcanizing and molding it, and then desorbing it. To facilitate desorption, a mold release agent is applied to the mold. Has been.

  Silicone is used as such a release agent, but it is necessary to use a detergent or the like in order to remove the release agent adhering to the rubber hose after vulcanization, and improvement thereof is required. Therefore, Patent Document 1 discloses an alkylene oxide adduct of glycerin fatty acid ester as a release agent that can be removed with water.

JP 2008-201010 A

  However, the mold release agent described in Patent Document 1 has a problem that the detergency is not sufficient. Therefore, there is a problem that the process of removing the release agent attached to the vulcanized rubber or the mold takes time and the productivity is inferior.

  Therefore, the present invention provides a release agent that is excellent in releasability between a vulcanized rubber and a mold and is also excellent in detergency.

  The mold release agent for molding a vulcanized rubber according to the present invention contains an saccharide alkylene oxide adduct (A), and the saccharide alkylene oxide adduct (A) has a saccharide residue content and The sum total with the content of oxyethylene groups is 20 to 100% by mass.

  The saccharide alkylene oxide adduct (A) preferably has a number average molecular weight of 1,000 to 30,000.

  The release agent for molding vulcanized rubber according to the present invention preferably further contains a polyoxyalkylene polyol (B).

  The content of the polyoxyalkylene polyol (B) is preferably 20 to 500 parts by mass with respect to 100 parts by mass of the saccharide alkylene oxide adduct (A).

  When the vulcanized rubber mold release agent is used, the mold release property between the vulcanized rubber and the mold is excellent. Further, the mold release agent for molding vulcanized rubber is excellent in detergency and can be removed in a short time, so that the productivity of vulcanized rubber can be improved.

  The release agent for molding vulcanized rubber in the present invention contains an alkylene oxide adduct (A) of saccharide.

  In the saccharide alkylene oxide adduct (A) used in the present invention, the sum of the saccharide residue content and the oxyethylene group content is 20 to 100% by mass. By setting it within the above range, the releasability and cleaning properties are excellent. The sum of the content of saccharide residues and the content of oxyethylene groups is preferably 30 to 95% by mass, and more preferably 40 to 90% by mass. In the present specification, the saccharide residue is a group obtained by removing a hydrogen atom of a hydroxyl group to which an alkylene oxide is added from a saccharide.

  The saccharide alkylene oxide adduct (A) used in the present invention preferably contains 0 to 95% by mass of an oxyethylene group. By setting it within the above range, the releasability and detergency become more excellent. The content of the oxyethylene group is more preferably 10 to 90% by mass, and further preferably 20 to 85% by mass.

  Examples of the saccharide in the alkylene oxide adduct (A) of saccharide used in the present invention include sugar and sugar alcohol. Examples of the sugar include monosaccharides such as glucose, fructose, galactose and mannose, disaccharides such as sucrose, lactose, maltose and trehalose, and polysaccharides such as cellulose, amylose and chitin. Examples of the sugar alcohol include sorbitol, mannitol, maltitol, and erythritol. Of these, sucrose and sorbitol are more preferred because they have better cleaning properties.

  Examples of the alkylene oxide added to the saccharide include ethylene oxide, propylene oxide, butylene oxide, styrene oxide, glycidol, and tetrahydrofuran. Of these, a combination of ethylene oxide and propylene oxide is preferable because of better mold release and cleaning properties. In addition, when using combining ethylene oxide and propylene oxide, these mixtures may be added and you may add separately.

  Examples of the method for adding the alkylene oxide include known methods such as introducing alkylene oxide into a reaction vessel at 70 to 120 ° C. and 0 to 0.3 MPa in the presence of a saccharide and a catalyst and reacting with the saccharide. The method can be used.

  As the saccharide used for the alkylene oxide addition reaction, saccharide alone can be used, but from the viewpoint of reducing the viscosity of the reaction solution, it is preferable to use saccharide dissolved in a compound capable of dissolving saccharide. Examples of such compounds that can dissolve saccharides include hydroxyl-containing compounds other than saccharides such as water, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, glycerin, and trimethylolpropane. Of these, water is preferable because of its high solubility in sugars and easy distillation after the addition reaction. Moreover, it is preferable that the usage-amount of the compound which can melt | dissolve saccharides is 20 mass parts or less with respect to 100 mass parts of saccharides from a viewpoint of raising the ratio of the alkylene oxide added to saccharides.

  The catalyst used for the alkylene oxide addition reaction is not particularly limited. For example, alkali metals such as potassium hydroxide and sodium hydroxide, alkaline earth metals such as calcium hydroxide and magnesium hydroxide, diethanolamine, triethylamine and the like. Amines, cationic polymerization catalysts, double metal cyanide complex catalysts, and the like. The usage-amount of a catalyst is 0.01-5.0 mass parts with respect to 100 mass parts of saccharides, for example.

  The amount of alkylene oxide added in the saccharide alkylene oxide adduct (A) is preferably 10 to 500 mol per mol of saccharide. By setting it within the above range, the releasability and detergency become more excellent. The addition amount of the alkylene oxide is more preferably 20 to 400 mol, and further preferably 40 to 300 mol.

The saccharide alkylene oxide adduct (A) has an average hydroxyl value of 10 to 600 mgK.
It is preferable that it is OH / g. By setting it within the above range, the releasability and detergency become more excellent. The average hydroxyl value is more preferably 15 to 400 mgKOH / g, and further preferably 20 to 250 mgKOH / g. In addition,
The average hydroxyl value can be measured according to JIS K0070.

  The saccharide alkylene oxide adduct (A) preferably has a number average molecular weight of 1,000 to 30,000. By setting it within the above range, the releasability and detergency become more excellent. The number average molecular weight is more preferably 1500 to 20000, and further preferably 2000 to 16000.

The alkylene oxide addition reaction product may be further purified. By performing the purification treatment, the hydrophilicity can be maintained for a longer period. Examples of such purification treatment include adsorbent treatment and distillation treatment. Among these, the adsorbent treatment is preferable because the production process is easy.

The adsorbent treatment method is not particularly limited. For example, the alkylene oxide addition reaction product and the adsorbent are mixed using a stirrer or the like, the alkylene oxide addition reaction product is passed through an adsorbent packed column, and the like. Is mentioned. Among these, the method of mixing the alkylene oxide addition reaction product and activated carbon is preferable because the operation is simple. When a solvent such as water or an organic solvent is used, the adsorbent may be added after mixing with the alkylene oxide addition reaction product in advance, or the adsorbent is dispersed in the solvent and then mixed with the alkylene oxide addition reaction product. May be.

The adsorbent is for adsorbing and removing impurities contained in the alkylene oxide addition reaction product. Such an adsorbent may be in the form of powder, granules, or pellets, and is preferably in the form of powder. Examples of such an adsorbent include activated carbon, zeolite, and the like. Particularly, since the heat resistance of the hydrophilizing agent is more excellent, activated carbon is preferable, and the pH in a 1% by mass aqueous suspension is 4 to 11. Activated carbon is more preferable, and the pH is 4.5 to 7.5.
More preferred is activated carbon.

The amount of the adsorbent used is not particularly limited, but the alkylene oxide addition reaction product 10
It is preferable that it is 0.1-20.0 mass part with respect to 0 mass part, and it is more preferable that it is 1.0-10.0 mass part. By making the usage-amount of adsorption agent in the said range, a manufacturing process will become a simpler thing.

Moreover, it is preferable to use a solvent in the adsorbent treatment. By using the solvent, the viscosity of the alkylene oxide addition reaction product is reduced, and the purification treatment can be easily performed.

In the adsorbent treatment, in addition to the solvent, an antioxidant, an ultraviolet absorber, etc.
Various additives may be used.

  The release agent for molding a vulcanized rubber hose according to the present embodiment preferably further contains a polyoxyalkylene polyol (B) in addition to the alkylene oxide adduct (A) of the saccharide. By containing the polyoxyalkylene polyol (B), the releasability is further improved.

  The polyoxyalkylene polyol (B) used in the present embodiment contains 20 to 80% by mass of oxyethylene groups when the total amount of oxyalkylene groups contained in the polyoxyalkylene polyol (B) is 100% by mass. It is preferable. By making the content of the oxyethylene group within the above range, the releasability and detergency become more excellent. The content of the oxyethylene group is preferably 30 to 75% by mass, and more preferably 40 to 70% by mass.

  The polyoxyalkylene polyol (B) preferably has a number average molecular weight (Mn) of 2000 to 20000. By using a material having such a number average molecular weight, the viscosity of the release agent becomes lower and workability can be improved. The number average molecular weight of the polyoxyalkylene polyol (B) is more preferably 3000 to 10,000.

  The manufacturing method of the said polyoxyalkylene polyol (B) is not specifically limited, It can manufacture using the synthesis method of a well-known polyoxyalkylene polyol (B). For example, when it manufactures by alkylene oxide addition polymerization, it is obtained by adding an alkali catalyst or an acid catalyst to a polyol, and making alkylene oxide react at 80-150 degreeC. Moreover, the addition form in the case of 2 or more types of alkylene oxides may be block addition or random addition, and these may be combined. Among these, since the mold release property is more excellent, it is preferable that the addition form includes block addition.

  The polyol that can be used for producing the polyoxyalkylene polyol (B) is not particularly limited, and examples thereof include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, Diols such as 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol and 3-methyl-1,5-pentanediol, triols such as glycerin and trimethylolpropane, And tetraols such as pentaerythritol. Of these, diols and triols are preferred because they are more excellent in releasability.

  The content of the polyoxyalkylene polyol (B) is preferably 20 to 500 parts by mass with respect to 100 parts by mass of the saccharide alkylene oxide adduct (A). By setting it within the above range, the releasability becomes more excellent. The content of the polyoxyalkylene polyol (B) is more preferably 30 to 300 parts by mass, and 40 to 250 parts by mass with respect to 100 parts by mass of the alkylene oxide adduct (A) of the saccharide. Further preferred.

  The release agent for molding vulcanized rubber of the present invention may be diluted with water. For example, the concentration of the saccharide alkylene oxide adduct (A) or the mixture of the saccharide alkylene oxide adduct (A) and the polyoxyalkylene polyol (B) is preferably 10 to 60% by mass, more preferably The thing diluted with water so that it may become 20-50 mass% is mentioned.

  The release agent for molding a vulcanized rubber according to the present invention may contain a known release agent component such as a nonionic or anionic surfactant or silicone as long as the effect is not impaired.

  The mold release agent for molding vulcanized rubber of the present invention includes an acrylonitrile-butadiene copolymer rubber (NBR), an ethylene / propylene / diene copolymer rubber (EPDM), and a rubber (NBR) blended with NBR and polyvinyl chloride (PVC). / PVC), acrylic rubber (ACM), fluorine rubber (FKM), etc., can be used for known rubbers. The rubber can contain known additives such as a vulcanizing agent, a vulcanizing aid, a processing aid, a plasticizer, a process oil, carbon black, a white filler, and an antioxidant.

  The rubber can be vulcanized and molded according to a conventional method. For example, after applying the release agent of the present invention to a mold and mounting the rubber, it may be heated and vulcanized. After vulcanization, the rubber is removed from the mold, and the release agent adhering to the rubber surface is washed with water or warm water to obtain a vulcanized rubber.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these.

  The number average molecular weight was measured by the following method.

(Measurement method of number average molecular weight)
The number average molecular weight was determined by the GPC method. The GPC apparatus and analysis conditions are as follows, and those calibrated with polyethylene glycol having molecular weights of 327, 2000, 8250 and 19700 were used as standard samples.
GPC device: System controller: SCL-10A (manufactured by Shimadzu Corporation)
Detector: RID-10A (manufactured by Shimadzu Corporation)
Column: Concatenated Shodex GPC KF-G, KF-803, KF802.5, KF-802, KF-801 (all manufactured by Showa Denko KK)
Eluent: Tetrahydrofuran Sample injection: 0.5 wt% solution, 80 μL
Flow rate: 0.8mL / min
Temperature: 25 ° C

  The raw materials used in this example are as follows.

<Adduct of saccharide alkylene oxide (A)>
(Production Example 1)
A stainless steel autoclave was charged with 342 g (1 mol) of sucrose, 70 g of water, and 3 g of potassium hydroxide, and the inside of the reactor was purged with nitrogen. The temperature was raised to 80 ° C. to dissolve sucrose, then the temperature was raised to 100 ° C., and 580 g (10 mol) of propylene oxide was introduced while maintaining the internal pressure at 0.3 MPa or less. After the introduction, the reaction was further carried out at 100 ° C. for 2 hours. Subsequently, 1320 g (30 mol) of ethylene oxide was introduced while maintaining the internal pressure at 0.3 MPa or less. After completion of the introduction of ethylene oxide, an alkylene oxide adduct was obtained by reacting at 100 ° C. for 2 hours.
100 g of the obtained alkylene oxide adduct and 30 g of water were mixed and adjusted to 50 ° C., and acetic acid was further added to adjust the pH to 6. Subsequently, 10 g of powdered activated carbon (trade name: Strong Shirasagi A (manufactured by Nippon Enviro Chemicals, 1% aqueous solution pH: 4.9) was added and stirred for 2 hours at 50 ° C. Thereafter, the activated carbon was removed by filtration. By removing water at 90 ° C. under reduced pressure, a sucrose-propylene oxide (10 mol) -ethylene oxide (30 mol) block adduct (a-1) was obtained (number average molecular weight: 2250, saccharide residue). Sum of the content of the groups and the content of the oxyethylene groups: 74% by weight)

(Production Example 2)
The same operation as in Production Example 1 was carried out except that the amount of propylene oxide used was 1160 g (20 mol) and the amount of ethylene oxide used was 6600 g (150 mol), and sucrose-propylene oxide (20 mol) -ethylene oxide (150 Mol) Block adduct (a-2) was obtained. (Number average molecular weight: 8100, total of saccharide residue content and oxyethylene group content: 86% by weight)

(Production Example 3)
The same operation as in Production Example 1 was performed except that the amount of propylene oxide used was 5800 g (100 mol) and the amount of ethylene oxide used was 8800 g (200 mol), and sucrose-propylene oxide (100 mol) -ethylene oxide (200 Mol) Block adduct (a-3) was obtained. (Number average molecular weight: 15000, sum of saccharide residue content and oxyethylene group content: 61% by weight)

(Production Example 4)
A stainless steel autoclave was charged with sucrose 342 (1 mol), water 70 g, and potassium hydroxide 3 g, and the inside of the reactor was purged with nitrogen. The temperature was raised to 80 ° C. to dissolve sucrose, and then the temperature was raised to 100 ° C., and a mixture of propylene oxide 1740 g (30 mol) and ethylene oxide 3080 g (70 mol) was introduced while maintaining the internal pressure at 0.3 MPa or less. . After completion of the introduction, an alkylene oxide adduct was obtained by further reacting at 100 ° C. for 2 hours. The obtained alkylene oxide adduct was purified by the same method as in Production Example 1 to obtain sucrose-propylene oxide (30 mol) / ethylene oxide (70 mol) random adduct (a-4). (Number average molecular weight: 5100, sum of saccharide residue content and oxyethylene group content: 66% by weight)

(Production Example 5)
The same procedure as in Production Example 1 was carried out except that the amount of propylene oxide used was 928 g (16 mol) and ethylene oxide was not used to obtain a sucrose-propylene oxide (16 mol) adduct (a-5). (Number average molecular weight: 1300, sum of saccharide residue content and oxyethylene group content: 27% by weight)

(Production Example 6)
The same operation as in Production Example 1 was performed except that propylene oxide was not used and the amount of ethylene oxide used was changed to 1760 g (40 mol) to obtain a sucrose-ethylene oxide (40 mol) adduct (a-6). (Number average molecular weight: 2100, sum of saccharide residue content and oxyethylene group content: 100% by weight)

(Production Example 7)
Except that 182 g (1 mol) of sorbitol was used instead of sucrose, the same operation as in Production Example 2 was performed to obtain a sorbitol-propylene oxide (20 mol) -ethylene oxide (150 mol) block adduct (a-7). It was. (Number average molecular weight: 8000, sum of saccharide residue content and oxyethylene group content: 87% by weight)

(Production Example 8)
The same operation as in Production Example 5 was carried out except that 182 g (1 mol) of sorbitol was used instead of sucrose to obtain a sorbitol-propylene oxide (30 mol) / ethylene oxide (70 mol) random adduct (a-8). It was. (Number average molecular weight: 5000, total of saccharide residue content and oxyethylene group content: 65% by weight)

<Polyoxyalkylene polyol (B)>
The type and ratio described in Table 1 were used in which alkylene oxide was added to 1 mol of polyol. In the table, EO in the type of alkylene oxide represents ethylene oxide, and PO represents propylene oxide. Moreover, EO in alkylene oxide content shows oxyethylene group content, PO shows oxypropylene group content, and all are content when the whole oxyalkylene group is 100 mass%.

<Other raw materials>
(C-1) Glycerin (c-2) Polyethylene glycol (number average molecular weight: 4000)
(C-3) Dimethylpolysiloxane (trade name: KF-96-20CS, manufactured by Shin-Etsu Chemical Co., Ltd.)
(C-4) Alkylene oxide adduct of glycerin fatty acid ester The same procedure as in Production Example 4 was conducted except that 292 g (1 mol) of glycerin monolaurate was used instead of sucrose, and an alkylene oxide adduct of glycerin fatty acid ester was obtained. (C-4) was obtained.

(Examples 1-15, Comparative Examples 1-4)
A release agent was obtained by mixing each raw material at a ratio (mass ratio) described in Table 2 below. The following evaluation was performed using this mold release agent. In the table, “dimethylpolysiloxane” is KF-96-20CS (trade name) manufactured by Shin-Etsu Chemical Co., Ltd.

(Releasability)
Unvulcanized rubber (ethylene / propylene / diene rubber (EPDM) or acrylonitrile-butadiene copolymer rubber (NBR)) coated with a release agent was mounted on a mold (120 × 120 × 2 mm). Subsequently, vulcanization treatment was performed at 150 ° C. for 1 hour, and the vulcanized rubber was taken out from the mold. The workability at this time was defined as releasability, and evaluation was performed according to the following criteria. The results are shown in Table 2.
○: Workability is the same as when dimethylpolysiloxane is used. ×: Workability is worse than when dimethylpolysiloxane is used.

(Cleanability)
The vulcanized rubber obtained by the above evaluation of releasability is immersed in 2 L of water (temperature: 80 ° C.), and the surface of the vulcanized rubber is confirmed 30 seconds, 1 minute and 2 minutes after the start of immersion. And evaluated according to the following criteria. In addition, when there is slime on the surface of the vulcanized rubber, the release agent remains, and when there is no slime, it indicates that no release agent remains. The results are shown in Table 2.
A: There is no slime on the surface of the vulcanized rubber after immersion for 30 seconds. B: There is no slime on the surface of the vulcanized rubber after immersion for 1 minute. C: There is no slime on the surface of the vulcanized rubber after immersion for 2 minutes. D: Immerse for 2 minutes. After that there is slime on the surface of the vulcanized rubber

  As is clear from Table 2, it can be seen that the release agent for molding a vulcanized rubber of the present invention is excellent in mold release and cleanability. Further, by using the saccharide alkylene oxide adduct (A) and the polyoxyalkylene polyol (B) in combination, sufficient release properties can be obtained even with a small amount of release agent, and cleaning properties are excellent. I understand. On the other hand, like Comparative Examples 1-4, when not containing the alkylene oxide adduct (A) of the saccharide | sugar of this application, it turns out that washing | cleaning property and mold release property cannot be made compatible.

Claims (4)

A release agent for molding a vulcanized rubber containing an alkylene oxide adduct (A) of a saccharide,
The alkylene oxide added to the saccharide is one or more compounds selected from the group consisting of ethylene oxide, propylene oxide, butylene oxide, styrene oxide, glycidol, and tetrahydrofuran,
Vulcanization wherein the sum of the content of saccharide residues and the content of oxyethylene groups in the saccharide alkylene oxide adduct (A) is 20 to 100% by mass of the saccharide alkylene oxide adduct (A). Release agent for rubber molding.   The mold release agent for vulcanized rubber molding according to claim 1, wherein the alkylene oxide adduct (A) of the saccharide has a number average molecular weight of 1,000 to 30,000.   Furthermore, the mold release agent for vulcanized rubber shaping | molding of Claim 1 or 2 containing a polyoxyalkylene polyol (B).   The mold release for vulcanized rubber molding according to claim 3, wherein the content of the polyoxyalkylene polyol (B) is 20 to 500 parts by mass with respect to 100 parts by mass of the alkylene oxide adduct (A) of the saccharide. Agent.