JPS6158084B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a resin composition comprising a combination of a low-viscosity, liquid modified benzyl ether type phenolic resin and a polyisocyanate. Although the modified phenol formaldehyde resin of the present invention is not limited to this, it can be particularly suitably applied to applications in which the resin is cured through a urethane bond with a polyisocyanate having at least two or more isocyanate groups. It is something that can be done. [Prior Art] As is well known, phenol formaldehyde resin is produced by reacting 1 mole of phenol with 1 mole or less of formaldehyde using an acidic catalyst, and a novolak resin produced by reacting 1 mole of phenol with 1 mole or less of formaldehyde, and 1 mole of formaldehyde.
It is broadly divided into resol resins, which are produced by reacting less than one mole amount using an alkaline catalyst. In general, novolac type resins are solid at room temperature, and because there are few sources of formaldehyde to serve as bonding groups, it is easy to adjust the molecular weight even when concentrated at high temperatures, but on the other hand, they do not have the property of retaining liquid by themselves. do not have. Therefore, when producing a cured product using a urethane reaction with a polyisocyanate such as methylene diisocyanate (hereinafter referred to as MDI) or tolylene diisocyanate (hereinafter referred to as TDI), it is necessary to make it into a solution with some kind of solvent or to use propylene as a solution. It is common to use polyether polyol with alkylene oxide such as oxide or ethylene oxide to form a liquid polyhydroxy compound, or to mix it with other polyol components and use it as a liquid mixture. On the other hand, since resol resin has a large formaldehyde component in terms of chemical equivalent, it has a large amount of methylol groups bonded to it, and when heated, a chemical reaction progresses, and it has the property of thermosetting itself and becoming insoluble and infusible. Therefore, in order to concentrate the resin, free moisture is removed at low temperature, but it is necessary to leave a large amount of residual moisture or unreacted monomer to retain the liquid, or to add a solvent to the highly viscous resin after concentration. It is made into a liquid. When producing a cured product from this resol resin and polyisocyanate using a urethane reaction, it contains a solvent and a large amount of water. Generates carbon dioxide gas, which significantly deteriorates the performance of the cured product. [Object of the invention] The modified benzyl ether type phenol formaldehyde resin which is the object of the present invention is the above-mentioned 2
In other words, it has properties intermediate between novolac resin and resol resin, and in addition to having a benzyl ether bond in its resin structure, it also has a methylene bond like novolac resin and a methylol group like resol resin. It is a resin that is particularly effective for urethane bonding, which is shared by all three. As a prior art that is close to the present invention, there is
73094 and Japanese Patent Application Laid-Open No. 51-38385 are known, but since the former produces a semi-solid phenol formaldehyde resin and the latter produces a solid phenol formaldehyde resin, these do not work at room temperature. It must be said that this resin is significantly different from the phenol formaldehyde resin of the present invention, which is always in a liquid state without the addition of an organic solvent. [Summary of the Invention] According to the present invention, (i) it contains substantially no solvent, maintains a stable liquid state at room temperature, contains 7% or less of free phenol, and has a ratio of methylol groups to benzyl ether groups; Provided is a resin composition comprising a combination of a liquid benzyl ether type phenol resin having a viscosity of 700 to 25,000 cps at 30°C and containing a benzyl ether group, a methylol group, and a methylene group of 0.5 to 2.5, and (ii) a polyisocyanate. . [Detailed Description of the Invention] What is surprising about the benzyl ether type phenol formaldehyde resin of the present invention is that its molecular weight distribution is concentrated at a significantly lower area than that of conventionally known resins, and it exhibits low viscosity. . That is, the molecular weight distribution of the resin is measured. GP
C. (gel permeation chromatography), as shown in FIG. On the other hand, the benzyl ether type phenol formaldehyde resin according to the present invention retains the necessary component peaks while suppressing the growth of the polymer. Therefore, it always exhibits a stable liquid state with low viscosity at room temperature, and there is no need to liquefy it by adding a solvent, for example, to obtain the desired low viscosity, and it also has the disadvantage of unnecessarily solidifying itself. It's something that doesn't exist. The reason why the modified resin of the present invention is particularly suitable for urethane reactions is that, like novolac resins and resol resins, it has a pH range of 4 to 7, not 3 or less or 8 or more, and is weakly acidic. This is because it is neither acidic (slow curing) nor alkaline (cures too quickly), and the catalyst used in the production of the resin has an intermediate catalytic effect as a nucleophile to generate the urethane reaction. Seem. To produce the benzyl ether type phenol formaldehyde resin according to the present invention, first, phenols and formaldehyde are reacted in an aqueous system with the addition of a suitable catalyst to form an initial condensate. This is quite surprising since, as is well known, the presence of water has heretofore been highly frowned upon in carrying out reactions of this type. Conventionally, operating in an anhydrous state is not only extremely difficult, but the reaction mixture has a high viscosity, is difficult to stir, and consumes a large amount of power and input. However, according to the method according to the present invention, it has been found that the presence of water contributes to the action as a kind of flushing agent in the next step and can significantly speed up the treatment step. It also has a great effect of suppressing the excessive progress of the initial condensation reaction. Although this initial condensation reaction can be carried out either batchwise or continuously, it is generally preferable to carry out the batchwise process. Next, the initial condensate containing unreacted monomers and water obtained as described above is passed through a heated long tube to vaporize the water and unreacted monomers, and the initial condensate is released from the vapors. The polycondensation reaction is carried out in the liquid phase independently of the compound. When this second step is completed, the reaction mixture thus obtained is introduced into an atmosphere of 100°C or higher and reduced pressure, and the vaporized water and unreacted monomers are taken out of the system, and the condensed resin is removed. The purpose is to obtain Note that, if necessary, the above-mentioned second step and third step can be carried out as a continuous operation in a single long tube. Furthermore, in order to make the entire process continuous, it is also possible to carry out the process as successive steps in a single tube. [Examples] Examples of the present invention will be described below, but it goes without saying that the technical scope of the present invention is not limited to these Examples. Example 1 282Kg of phenol and 47% formalin at 287℃
was placed in a reaction vessel with stirring, and then 1.4 kg of lead naphthenate and 0.3 kg of zinc oxide were added and the mixture was heated to 100 ml from room temperature.
The temperature was raised to ℃ in about 60 minutes. The resin viscosity when reacted at 100°C for 5.5 hours was 290 centipoise (hereinafter referred to as CP) at 30°C (Product A). Then L=23m and D=0.023 (L/D=
1000), the inlet is 1.5Kg/
cm ² , heated steam of 3.5 Kg/cm ² in the middle and 3.0 Kg/cm ² at the outlet, and the product A was passed through it at a pressure of 0.8 Kg/cm ² ,
It was injected at a flow rate of 50Kg/hr. An evaporator was installed at the outlet of the heating tube, and the temperature was set at 60 mmHg to 100 mmHg and 125° C. to perform vacuum concentration. The properties of the concentrated resin are viscosity 2500cp/30℃,
Non-volatile content is 85% at 180℃ x 60 minutes, moisture content is 1% by Karl Fischer method, free phenol content is 5.0% by liquid chromatography, free formaldehyde content is 0.3% by hydroxylamine hydrochloride method, and IR method. The ratio of methylol group/benzyl ether group was 1.1. In addition, the OH value by the acetylation method, which is a combination of phenolic hydroxyl groups and methylol hydroxyl groups, is 490 ~
500 (Product-I). Comparative Example 1 After carrying out a condensation reaction under the formulation conditions shown in Table 1, dehydration was carried out under reduced pressure at 100 mmHg while raising the temperature from 100°C to 125°C in a reaction vessel equipped with a heating jacket. It takes about 30 minutes to reach 125℃, and after reaching 125℃,
The reaction product was immediately discharged, spread widely on a saucer, and cooled while blowing air to obtain a resin of Comparative Example 1. Examples 2 to 4 In the same manner as in Example 1, resins were produced by reacting and concentrating under the various conditions shown in Table 1, and the products shown in Table 1 were obtained.

【table】

[Table] Example 5 30 parts of the product-I according to Example 1 and 12.5 parts of Freon 11 (S-1 manufactured by Daikin Industries) as a blowing agent,
Mix 1 part of foam stabilizer L-5420 (manufactured by Nippon Unicar) and 1.1 parts of a mixture of 4-phenylpropylpyridine and dibutyltin dilaurate as a curing accelerator, add 40 parts of methylene diisocyanate (MDI), and stir at high speed. It was made into a phenol urethane foam material. At this time, cream time is 10 seconds, rise time is 23
The curing time was 35 seconds, and the resulting foam had a density of 0.019 g/cm ³ and a very uniform foam with a closed cell ratio of 85%. In total, the dimensional change rate of the foam was less than +5% in both the vertical and horizontal directions after being left in an oven at 150°C for 20 hours, and the weight change rate was -1%, making it extremely stable. Example 6 Product - When compounding in the same manner as in Example 5, ammonium polyphosphate powder was added as a flame retardant in an amount of 7% based on the total of resin and polyisocyanate to produce a foam. While known polyether polyol foams rapidly combust and burn out when ignited, this foam exhibited high heat resistance so that even when ignited, it did not burn and was carbonized without a flame. Example 7 Weighed 1 part of the product and 1 part of MDI to 100 parts of silica sand (Australian silica sand) into a Shinagawa mixer, and added 1 part of 4-phenylpropylpyridine to the resin as a curing accelerator. % added,
The mixture was kneaded for 30 seconds to form a test piece for a casting model. Table 2 shows the results of measuring the resistance pressure according to test method HM-1 set by the Casting Technology Promotion Association. For comparison, a resin solution prepared by dissolving the resin of Comparative Example 1 in a 60% mixed solvent of ethyl cellosolve acetate and a petroleum solvent was added at a rate of 1.3 parts to 100 parts of silica sand.
1.3% MDI organic solvent (Hysol) 75% solution
A similar strength test was conducted by molding a mold containing the same amount. As shown in Table 2, the mold strength is sufficient to allow use without the use of organic solvents, and there is no odor from organic solvents during molding work, greatly improving the working environment, and there is no organic solvent remaining in the mold. Therefore, the amount of gas generated at 1000℃ was reduced by 40%.

[Table] Example 8 While uniformly mixing 200 parts of silica sand powder, 2 parts of glass wool, and 2 parts of spirit black, the product -
100 parts of MDI and 100 parts of MDI were added to form a slurry, which was poured into a mold to form a composite. 24 hours after being left at room temperature
The transverse rupture strength was measured over time and found to be 250 Kg/cm ² . Since this complex does not contain organic solvent, it can be heated at 150℃.
After heat treatment for 60 minutes, the strength was 350 Kg/cm ² , the shrinkage rate was 0%, and the weight change rate was 0%. Example 9 15 parts of the product were mixed with 100 parts of wood flour, and after thorough mixing, 15 parts of MDI was added and mixed. A pressure of 200 kg/cm ² was applied to the mixture in a metal frame measuring 300 x 300 x 5 m/m to obtain a molded product cured at room temperature. The strength of the molded product gradually increased at room temperature, reaching the maximum strength after about 3 hours, and an artificial wooden board could be obtained, and the molded product could be fully used as a building material without the odor of organic solvents. Example 10 20 parts of the product for 100 parts of aluminum powder
A slurry was prepared by mixing 20 parts of MDI and 20 parts of MDI, and poured into a silicone rubber box model prepared in advance without a curing catalyst. After 30 minutes, the cured product was taken out to obtain a molded product. This material is easy to cut with a knife when the curing reaction has not progressed sufficiently.
It had the property of being able to change its shape freely. After about 5 hours, the molded product could no longer be cut with a knife and became a very hard molded product, which could be fully used as a mold model for casting or a resin mold for molding. In this specification, methods for measuring several pieces of data described in relation to the present invention will be explained as follows. 1. Viscosity measurement method A sample is taken in a 500 c.c. polyethylene beaker, the sample temperature is adjusted to 30°C, and then measured using a BH type viscometer (manufactured by Tokyo Keiki Seisakusho Co., Ltd.) at a rotor rotation speed of 20 rpm. 2. Method for measuring the amount of free phenol (a) Measuring device Liquid chromatography HLC802
(Manufactured by Toyo Soda Kogyo Co., Ltd.) (b) Column body GH8P×G1000H8×G2000H8
(Manufactured by Toyo Soda Kogyo Co., Ltd.) (c) Carrier Tetrahydrofuran (THF)
(abbreviated as) (d) Sample for measurement: Accurately weigh approximately 1 g of liquid resin.
Use the sample dissolved in 100 ml of THF.
(Use a 100ml volumetric flask) (e) Create a calibration curve Add phenol (special grade reagent)
Seven standard samples, weighed appropriately within the range of 0.01 to 0.2 g and dissolved in 100 ml of THF, were injected into liquid chromatography HLC802, and the peak height (mm) and phenol concentration (mg/ 100ml) to create a calibration curve. (f) Measurement method Inject the measurement sample into liquid chromatography HLC802, calculate the amount of phenol A (mg) from the peak height (mm) obtained using the above calibration curve, and calculate the amount of free phenol (%) using the following formula. ) is calculated. Amount of free phenol (%) = A/Amount of liquid resin (mg) × 100 3 Measuring method of methylol group/bendiether group ratio (a) Measuring instrument Infrared absorption spectrum IRA-1
(Manufactured by JASCO Corporation) (b) Sample for measurement Use a 50% by weight acetone solution of liquid resin as the sample. (c) Measurement method The longest peak position of the characteristic absorption band (950 to 1040 cm ^-1 ) attributed to the methylol group and the characteristic absorption band (1040 to 1080 cm ) attributed to the benzyl ether group obtained by the liquid film method (NaCl plate sandwich method) ^-1 ) Find the absorption intensity at the longest peak or shoulder position, and calculate the ratio using the following formula. As explained above, the resin composition formed by combining the liquid benzyl ether type phenolic resin and polyisocyanate of the present invention can be applied to a wide range of applications such as foaming materials, molds, building materials, sealing materials, etc.
It is a valuable resin composition that provides good results. When using the liquid benzyl ether type phenolic resin according to the present invention for urethane reaction,
When making various molded objects, it is very effective to use it without a solvent, but there are no restrictions on diluting it with an organic solvent to make it even lower in viscosity and use it in adhesives and the like.

[Brief explanation of the drawing]

Figure 1 shows GPC comparing the present invention and conventional products.
Figure 2 is a chart showing an example of a graph used to measure the ratio of methylol group/benzyl ether group, with the vertical axis showing the transmission percentage and the horizontal axis showing the wave number. It is shown in cm ^-1 .

Claims (1)

[Claims] 1 (i) Substantially contains no solvent, maintains a stable liquid state at room temperature, contains 7% or less of free phenol, and has a ratio of methylol groups to benzyl ether groups.
Viscosity at 30℃ is 700, including benzyl ether group, methylol group and methylene group, which is 0.5-2.5
A resin composition comprising a combination of a liquid benzyl ether type phenolic resin of ~25,000 cps and (ii) a polyisocyanate.