JPS60152532A - Production of polymer foam - Google Patents

Abstract

PURPOSE:To obtain an open-cellular polymer foam having a uniform fine cell distribution, high strength, and excellent heat resistance, by curing a liquid mixture of PVA, a water-soluble thermosetting resin and a powdered phenolic resin by adding a curing agent thereto. CONSTITUTION:A liquid mixture of polyvinyl alcohol, a water-soluble thermosetting resin and a particulate or powdered phenolic resin is cured by adding a curing agent. According to this process, it is possible to form cells without cell- forming agent by the interaction among the polyvinyl alcohol, the water-soluble thermosetting resin and the reactive particulate or powdered phenolic resin. By varying the mixing ratio among these components, it is possible to control the form, diameter distribution, etc., of cells and to produce a polymer foam having fine uniform open cells.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves mixing polyvinyl alcohol, a water-soluble thermosetting resin, and a reactive granular or powdered phenolic resin, adding a curing agent, and creating fine continuous pores for reaction curing. We are excited about the manufacturing method of porous polymer materials.

1. Polyvinyl acetal yarn porous material was manufactured by a new acetathal reaction in which polyvinyl alcohol mixed with cotton wool or other porous material was reacted with dialdehydes using an acid catalyst, and its continuous pore characteristics were improved. It has been used as an excellent filter material due to its commercial porosity.

However, with the advancement of V-filtration technology in recent years, the performance requirements for cutting LNP filter materials have become increasingly strict, and even in the currently widely used cartridge-type filter materials, high strength and heat resistance are required. There is a growing demand for filters that have excellent filtration performance and high precision. However, in the conventional manufacturing method of polyvinyl acetal-based porous materials, the pore diameter of the porous material is limited by the particle size of the pore-forming phase. The current situation is that it is difficult to run when manufactured.

In addition, polyvinyl acetal porous materials swell due to moisture absorption, resulting in poor shape retention and striking properties.To improve this, it is necessary to apply LC resin treatment, and they also have drawbacks such as poor heat resistance. are doing.

The inventor of the present invention, Nagisa et al., completed the present invention as a result of intensive research to improve the above-mentioned drawbacks of conventional polyvinyl acetal porous materials, and the aim is to achieve a uniform and fine pore distribution, A new porous polymer material with continuous pores that has high strength and excellent heat resistance! ! ! ! The manufacturing method is provided in full.

Add the above-mentioned thermosetting T# fat and reactive granular or powdery phenolic resin with water solubility to polyvinyl alcohol/l/fur, add a curing agent, and react and cure. This is achieved by

The remarkable feature of the present invention is that, without using a pore-forming material as in the past, it is possible to use polyvinyl alcohol and water-soluble ripe hardening resin and reactive granular powder.
a. By Aiyu □Eye, mind, □It is something that can be formed,
By changing the mixing ratio of these components, it is possible to control the pore morphology and pore size distribution to produce a polymeric porous body having fine and uniform continuous pores.

Polyvinyl 7 to Co ρ used in the present invention is generally obtained by saponifying vinyl acetate, and its degree of polymerization,
There is no particular sub@ such as saponification degree, branching, copolymerization with other senomers, etc., and it can be used alone or in combination of two or more types, but
Preferably ii polymerization degree 100 to 5,000, saponification degree 70
It is preferable that the amount is mol% or more.

In addition, 1. Water-soluble thermosetting resins such as water-soluble reso-/I/sl resins, melamine resins, urea resins, etc. are suitable.

Resol/I/brews are initial products obtained by reacting phenols with a/L' ghydes in the presence of basic catalysts, and are usually rich in methylo-ρ groups and have a molecular weight of about 6.
Although it is a self-thermal crosslinking phenol resin with a molecular weight of less than 00, it is generally used to react phenol/I/1 mo with aldehydes of 1.5 to 6.5 mo in the presence of a slightly supercharged alkali catalyst. By keeping the resulting initial condensate in a stable water-soluble state, a water-soluble resin A/resin can be obtained.

Melamine resin and urea resin are initial combinations of formaldehyde and formaldehyde, respectively, and are soluble in water.

The curing agent used in the present invention also contains a curing catalyst for curing water-soluble thermosetting resins. Examples of curing agents for phenolic resins include hydrochloric acid, oxalic acid, lactic acid, formic acid, acetic acid, and para-toluenesulfone. Acids such as benzyl sulfonic acid are suitable, and as curing agents for melamine resins and urea resins, inorganic acids such as Fi hydrochloric acid and sulfuric acid, various carboxylic acid esters such as dimethyl oxalate, ethylamine hydrochloride and triethanolamine hydrochloride are suitable. Hydrochlorides of amines such as the following can be used. In addition, these curing agents may be used in combination with a crosslinking agent for polyvinyl alcohol such as formaldehyde or benzaldehyde, especially when the amount of polyvinyl alcohol blended is larger than that of water-soluble thermosetting resins. It is desirable to use these agents together. In addition to the above-mentioned crosslinking agents for polyvinyl alcohol, aldehydes such as acetaldehyde, propionaldehyde, 0-butyraldehyde, octylaldehyde, 2-ethylhexylaldehyde, glyoxal, and acrolein can be used.

In addition, the reactive granular or powdered phenolic resin of the present invention is a granular or powdered resin made of a condensate of phenols and forma/L-dehyde, and the resin absorbs infrared rays by the KBr tablet method. 1600c+++' in the spectrum (absorption peak attributed to benzene)
The absorption intensity of "14°., 990 Int, 1 (N5i
' (absorption peak attributed to the methylo-〃 group) with the highest absorption intensity in the range of two~, .15.890c++
+' (absorption peak of isolated hydrogen atom in benzene building) When the absorption intensity is expressed in Dwoo, D9. . ~,. +!
/”14°.=0.2~9.0,D,./D1..

=0.09~1.0, preferably Dtt0~+o+s/D+aoo=low 5~7,0, D
l, 0/D+aoo ~0-1~0.9 Especially nail-biting Dtt0-t. ts/D16011 ”’ ”’~5”
'D8vO/Dj400=0' It is a granular or powdery phenol/formua ρ dahyde resin having a ratio of 2 to 0.8%.

In the infrared absorption spectrum, Dl. . The peak of indicates the absorption attributed to the benzene wing, and Dtt. ~,. , 5
The peak of 6. shows an absorption attributable to the methylol group. . It is already widely known with regard to phenol-formaldehyde resin that the peak of the phenol-formaldehyde resin exhibits an absorption that is attributable to the isolated hydrogen atom of the benzene wing.

The reactive granular or powdered phenolic resin used in this triggering trap is "??.~1015/D+&OO"" 0-
The characteristic values of 2 to 9.0 indicate that the resin contains at least a certain amount of methylol groups and that the methylol base can be adjusted to a fairly large extent. .

&ICD,. -+o+s =0' 3 to 7.0, especially 0.4 to 5.0. The resins suitable for use in the present invention contain a moderate concentration of methylo-ρ groups and are very stable.

Furthermore, the resin has Ds in the infrared absorption spectrum ρ.
volD+boo = [l, 09-1. [l, j
l) Like a ;a # & :6ED6. . /D1400
= 0. -j ~ g, c), especially 0.12 ~ 0.8
The fact that the resin exhibits this property is due to the fact that the resin has the reaction sites (melt and para positions) of the phenol molecules involved in the reaction.
shows the fact that τ is significantly or moderately blocked by methylol groups.

Cured products of conventionally known resol resins are generally D99G-
joj67D1400 and Dat. /D + aoo ノ/D+400 is generally a lower value than the lower limit of 0.09 for the resin. As described above, the reactive granular or powdered phenolic resin used in the present invention is obtained by pulverizing a cured product of a conventionally known resol resin or a cured product of Novo 2 Tsuku M resin, or by pulverizing a cured product of a conventionally known cured novolac resin. It is completely different from the pulverized one, and is a phenolic resin made of spherical-order particles and secondary aggregates thereof, which is produced according to the production method described in Japanese Patent Publication No. 57-1770'11.

Granular f! having this reactivity! Lnl, powdered phenol/
Since its shape is close to spherical and it is a particle,
Compared to powder obtained by pulverizing known cured phenolic resins, it has better miscibility with polyvinyl alcohol and water-soluble thermosetting resins, and by using this resin, large amounts of phenol can be produced for the first time. /L' It becomes possible to obtain a porous polymer body having continuous pores in which the resin powder is uniformly mixed. In order to uniformly disperse the powder in the porous polymer material, the average particle size of the phenol fence powder must be #'i1 to 150 μm.
C'ru is preferred.

゛ In order to produce a porous polymer body having fine continuous pores using the above-mentioned polyvinyl alcohol, a water-soluble thermosetting resin, and a reactive granular or powdery phenol resin, a predetermined amount of polyvinyl alcohol is used. After adding an appropriate amount of water and heating and dissolving, add water-soluble thermosetting M fat and reactive granular powdered phenol/I/resin that has been previously dispersed in water. Stir, 40
After cooling to about 'C', a curing agent is added, mixed uniformly, transferred to a mold of a desired shape, and heated to react. After the reaction is completed, the molded product taken out from the mold may be washed with water to wash away unreacted substances, curing agent, etc. The shape of the molded product can be arbitrarily selected from plate-like, cylindrical, cylindrical, etc.

A blend of polyvinyl alcohol, water-soluble thermosetting Camphor 1K, and reactive granular or powdered phenol resin is mixed to produce a polymeric porous material having fine continuous pores by the above method. The amount is the concentration of isomorphic components in the mixed solution before mixing the curing agent, usually 0.5 to 15% by weight of polyvinyl alcohol, 6 to 55% by weight of water-soluble thermosetting resin, and reactive resin. 5 to 30% by weight of granular or powdered phenolic resin, preferably 1 to 12% by weight of polyvinyl alcohol, 5 to 45% by weight of water-soluble thermosetting resin, and reactive granular or powdered resin. Phenol/I/1M fat is 8-28% by weight, most preferably polyvinyl alcohol is 2-8% by weight.
, 8 to 40% by weight of water-soluble thermosetting resin, and 10 to 2% of reactive granular or powdered phenolic plum fat.
It is 5% by weight.

In producing the porous polymer material having fine continuous pores according to the present invention, the advantage of incorporating reactive granular or powdered phenolic resin is that the phenolic resin powder is uniformly dispersed, thereby forming pores. The idea is to form fine, uniform, continuous pores without using any material.

Furthermore, the pheno-1vsl fat powder contributes to the development of strength of the porous body by reacting with the water-soluble thermosetting resin during the curing reaction process.

If the amount of the phenol/I/lI4 fat powder mixed in is too small, the pore distribution becomes uneven, and large voids are likely to be formed during the curing reaction, especially inside the sample, and cracks are likely to occur during the drying process after the curing reaction. The problem arises.

Furthermore, the number of independent pores increases, making it difficult to obtain a porous polymer having a high continuous porosity.

If the resin powder has too many points, it becomes bulky, and the workability during mixing of other raw materials is significantly reduced, and it is impossible to mix uniformly with one koji, making it impossible to obtain a good porous body.

Polyvinyl alcohol imparts a unique pore morphology to the porous polymer through interaction with the reactive granular or powdered phenol resin, and Ml helps to form fine continuous pores.
It plays a major role. When too little polyvinyl alcohol is present, the pore morphology does not necessarily change, but the pore distribution tends to become non-uniform. ′! If there are too many points [Fi
The viscosity of the mixed liquid increases and the workability is significantly impaired, making it impossible to obtain a good porous body.

In other words, if the water-soluble thermosetting resin is too small, the bonding strength between the granular or powdered phenolic resins in the obtained porous polymer will be low, resulting in a high strength a-like polymer porous material. I can't get the body. Multiple points of liquid phenolic resin
In this case, the number of vertical pores increases and the continuous porosity decreases, which is not preferable.

In addition, during the production of the above-mentioned porous polymer having fine continuous pores, resin powders such as phenol/L'-resin, 7-run resin, epoxy resin, fibrous materials, or silica, alumina, graphite, Silicon carbide, inorganic powder with a thick viscosity, charcoal! +4 Suitable fibrous materials such as fibers and asbestos! Even when mixed, the porous polymer body obtained as described above has
In addition, 11m of phenolic resin such as resol resin, novolac resin, etc., Furantoki, melamine resin, epoxy resin, etc.
It may also be impregnated with urea resin, pitch, Tar/L', etc., or made into fine stones.

Although a variety of known methods are available for producing the 4:r resins, most commonly, a given J)l resin prepared by the method described above is used. shape, size, pore diameter,
After immersing a porous polymer material with fine pores in a solution prepared by dissolving the aforementioned synthetic resin in a solvent,
Allow it to dry and harden.

The unexploded polymeric porous body thus obtained has uniform, fine, continuous pores, and a porous body with an average pore diameter of 10 #m or less can be easily obtained. In particular, when the solid content in the mixed liquid during production is large, the porous polymer material has extremely fine continuous pores with an average pore diameter of 1 μm or less. Further, the porous polymer material has the characteristics of high strength and low porosity.

The porous polymer material with such excellent properties has fine particles of 1k.
Ideal as a filter for filtration. Normally, fine particles with a particle size of a fraction of the average pore diameter are separated by a pore size filter that is used to separate fine particles such as dust and impurities in gases and liquids. Therefore, the filter of the present invention 1 is also suitable as a high-precision precision filter that filters fine particles of 1 μm or less. Furthermore, the I14 molecular porous material uses a thermosetting resin and has high strength and excellent heat resistance.

The polymeric porous material having fine continuous pores of ``Unexploded 9'' is suitable not only as a filter but also as an ILR heating material, a catalyst carrier, an aeration pipe, etc.

EXAMPLE 1 A predetermined amount of polyvinyl alcohol (degree of polymerization: 1700, degree of saponification: 99%) was dispersed in water and dissolved by heating.

This solution is mixed with a water-soluble resol resin (manufactured by Chowa Union Synthesis, IRT, -1586 (solid content concentration 70%)) and a predetermined amount of reactive granular phenol resin (made by Hoewa Union), which has been previously dispersed in water. Made by spinning, product name Beper/l
/8. (average particle size: 20 μm) was added and thoroughly mixed with stirring.

Water for volume adjustment was added to this mixture to adjust the volume of the mixture to 10%. The amount of each component in the mixture was measured in advance as shown in Table 1.

After adding an appropriate amount of formalin (67%) and para-toluenesulfonic acid aqueous solution R (50Mikgb) to the above mixture and stirring thoroughly, it was poured into a 300x square mold made of polyglopylene, and placed in a hot water bath at 75°C. The reaction was carried out at 20 o'clock in the same room, and after demolding, the polymer was washed in the shower for 4 days and dried at 80°C to obtain a porous polymer having fine continuous pores.The thus obtained polymer having fine continuous pores The properties of the porous body are shown in Table 1.

The average pore diameter of the porous material was measured by mercury intrusion method. It also has continuous porosity! I! It was measured using a gas comparison type hydrometer.

As shown in this example, by selecting the blending ratio of liquid pheno-N#iI fat and reactive granular pheno-/I/resin polyvinyl alcohol to m9Jvc, a polymer with fine continuous pores can be obtained. A molecular porous material was obtained.

$1 Table Example Z Houai degree 500. ff Horibinilua N:I with 99% fluoridation degree
In the same manner as in Example 1, an outer diameter of 70 mm and an inner diameter of 3 mm were prepared using a water-soluble thermosetting resin and a phenol resin powder.
(Iwa 11, a cylindrical porous polymer body t4T with a length of 250 mm was made.

Melamine resin (
Sumitex Resin M-5, 11 and urea resin (manufactured by Sumitex Chemical Industry Co., Ltd.)
Sumitex Resin ULY.

Solid content concentration 201f blood%) was used in combination, and Sumitex Resin ACX was used as a hardening agent.

In addition, as phenol isi sushi powder, reactive granular phenol powder (manufactured by Kobo@, part name: Belper A/
8. average particle size 15 μm), cured novolac fiber powder (
KF'02BT made by Nippon Kynor ■.

Fiber III length i m) and resol resin (manufactured by Gunei Chemical Industry ■, AP-106GK) were heated to 48 #flit at 160°C.
ltl! Phenol resin powder (
61fI paper with an average particle size of 20 μm) was used.

After heating and melting 600 tt of polyvinyl alcohol in the same manner as 9AJ1, Sumitex Resin Y-3,1
, 5J, Sumitex Resin ULY 1 kQ were added and mixed, and a predetermined amount of phenol resin powder previously dispersed in water and water for adjusting the liquid volume were added to make the mixed liquid volume 10k (/ hI, and thoroughly stirred and mixed.The phenol/silicone powder in the mixture is shown in Table 2.To this mixture, formalin (67 weight 9b)', 600W, and a hardening agent, Sumitic, were added. Nuresin 80X500F was added and a curing reaction was carried out in the same manner as in Example 1 to obtain a cylindrical porous polymer body.The physical properties of the porous polymer body are shown in Table 2.

This result shows that by using a granular phenolic resin with high compatibility, it is possible to obtain a good second layer with continuous pores.
For paleness and strength, cut out a 9x12x150+w test piece from a cylindrical sample. Add a water-soluble resol resin (manufactured by Juden Deerez ■, Sumilite Resin PR961A, solid content concentration 64% by weight) 1.5k (i.
A reactive granular phenol resin (manufactured by Kanebo ■, trade name Belper/I/8, average particle size 20 pm) at 700 V and Anuvest 1002 were added to adjust the liquid volume to 10 kQ, and then thoroughly stirred and mixed.

After mixing 700 liters of formalin (57% by weight) and 70 liters of sulfur ai2 (50% by weight) into the above mixture, 6
It was poured into a 00n square mold, reacted for 24 hours in a hot water bath at 70°C, and after demolding, washed in the shower for 48 hours and dried at 80°C to obtain a porous polymer having fine continuous pores. Ta. The continuous porosity of the polymer porous material is 72%, and the average pore diameter #: t
It was 6 μm.

Claims (1)

[Scope of Claims] (1) A fine microorganism characterized in that a curing agent is added to a mixed liquid consisting of polyvinyl alcohol, a water-soluble thermosetting resin, and a reactive granular or powdery phenolic resin, and the mixture is reacted and cured. A method for producing a porous polymer material having continuous pores. (2) The method for producing a porous polymer body according to claim (1), wherein the water-soluble thermosetting resin is a phenol resin, a melamine resin, a urea resin, or a mixture of two or more thereof. ( 5) Claims (1) or (+2) which are spherical-order particles having an average particle size of 1 to 150 μm and secondary aggregates thereof of a reactive granular or powdered phenolic resin.
A method for producing a porous polymer according to item 1. +41 The composition of 11 is polyvinyl alcohol 0.5-1
5% by weight, water-soluble thermosetting resin has a solid content of 3
55% by weight, and the reactive granular or powdered phenolic resin is in the range of 5 to 30% by weight. Manufacturing method.