JPS5927912A - Manufacturing method of polyurethane foam - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing polyurethane foam, and more particularly to a method for producing polyurethane foam, which has a low odor and a uniform low density.
This invention relates to a method for producing polyurethane foam using a specific catalyst that makes it possible to shorten the molding time without causing any discoloration even when used with other catalysts.

In the production of polyurethanes by reaction with polyisocyanates, polyols, and optionally other components, a wide range of catalysts are used, in which catalysts are used to balance multiple simultaneous reactions during the production process. One of the reactions that occurs in the polyurethane manufacturing process is the reaction between polyisocyanate and polyol, which produces polyurethane, which causes chain extension and increases viscosity. The reaction is a reaction between a polyisocyanate and an amine, which produces a urea bond, and chain extension.Another reaction is a reaction between a polyisocyanate and a urethane group or a urinary group, resulting in an allophanate bond or a chain extension. It creates biuret bonds and increases the crosslinking density of the polymer. “Another reaction is the reaction of polyisocyanate with water, which generates foam with the evolution of carbon dioxide. is not necessary when using other blowing agents.In order to obtain a good foam structure by these reactions, each reaction must be balanced, and foam generation must be coordinated with chain elongation. If the comparison is too fast, the form will collapse, and conversely, if the chain elongation is too fast compared to the formation of the form, the formation of the form will be restricted. Control of these reactions depends on the reaction conditions. Depending on the choice, the choice of catalyst is most important.

Many types of catalysts have been known for use in producing polyurethane foam, and they are selected depending on the physical properties required to achieve various physical properties. As a result, polyurethane is now required to have harsh properties as its uses have expanded to include automobile parts, furniture, and footwear.In other words, ■ short molding time; ■ short molding time; Good fluidity, ■ Low density of the resulting polyurethane foam, ■ Good low-temperature dimensional stability, ■ Low brittleness, ■ Easy adhesion to adherends when integrally molded, ■ Performance requirements include that the resulting polyurethane should not be discolored or cracked, and should have little odor, but it was impossible to satisfy all of these requirements.For example, in order to shorten molding time, catalyst If a large amount of urethane is added, the fluidity during foaming resin will be lost, resulting in poor filling properties, and the resulting polyurethane foam will be prone to discoloration and cracks. In addition, tertiary amines, which are conventionally widely used catalysts, are indispensable for producing Bo')' ZL/Tanform, especially when water is used as a blowing agent, but they have a significant odor and It is attached to the polyurethane foam molded products manufactured, significantly reducing the value of the products.

Therefore, the present inventors have made extensive research efforts to develop a catalyst that does not have such drawbacks and can exhibit the above-mentioned various performances at the same time.As a result, the present inventors have found that a certain tertiary amine exhibits satisfactory performance. They discovered this and completed the present invention.

That is, the present invention provides a method for producing polyurethane foam from a compound having a small number (both having two active hydrogens and having molecules [400 to 1 O,000), a polyisocyanate, water and/or a blowing agent, and the following general method. A polyurethane characterized by using a catalyst represented by the formula (84.R2 is the same or different alkylene group having 4 to 8 carbon atoms, preferably 4 to 6 carbon atoms, and n is a positive number of 1 to 4) The present invention provides a method for manufacturing foam.

The compound of formula (υ) according to the present invention can be produced by a method using known synthetic techniques.

The compound of the formula (IJ) according to the present invention is a N-methylpolyalkylenepolyamine whose alkylene group has 4 to 80 carbon atoms and is particularly preferred because it is linear or branched.
7( has 4 to 6 carbon atoms, and n is 1 to 2.

If the number of carbon atoms in the alkylene group is limited to less than 4, the odor will be significant, the foaming reaction will take precedence, the balance between foaming and gelation will be disrupted, and large and thick molded products will not be produced (
When the number is 8, the center part becomes discolored and cracks appear, and if the number exceeds 8, the activity as a catalyst decreases, making it impossible to achieve the purpose of shortening the molding time.

When the compound of formula α according to the present invention is used, the produced polyurethane foam has no amine odor (and it is possible to shorten the molding time). The resulting polyurethane foam has good dimensional stability and low brittleness (no discoloration or cracks), making it possible to make the polyurethane foam uniform and highly foamed (low density). A polyurethane foam can be obtained that exhibits good adhesion to adherends in the molding of sunglass panels, boxes, etc.

The compound of formula α] according to the present invention includes triethylenediamine, N+Nln'll-tetramethylalkylenediamine, N,N,)J'+N'IN''-pentamethyldiethylenetriamine, N,N-dimethylcyclohexylamine, N, It can also be used in a catalyst in combination with a known 6th class amine such as N-dimethylethanolamine.

When used together, the weight ratio of the compound of formula (1) and these amines is 100:1 to 1:100. In the production of high-strength urethane, especially hard high-density urethane, if triethylenediamine is used as a catalyst to shorten the molding time, it will cause burns and cracks, but the compound of formula α according to the present invention! 111! When I is used in combination, the molding time can be shortened without causing burns or cranks.

In addition, the compound of the formula (υ) according to the present invention can be used in combination with a tin-based catalyst.In order to shorten the molding time, using a tin-based catalyst that promotes the resinization reaction increases the curing speed. has poor fluidity and poor filling into the mold.Thus, tin-based catalysts such as triethylenediamine, N, N, N'
, N",N"-pentamethyldiethylenetriamine has been used in combination, but the filling properties are poor (
There are disadvantages such as high brittleness (and peeling from the adherend when demolding). However, when the compound 20 according to the present invention is used in combination with a tin-based catalyst, the resinization reaction is promoted, and It has good fluidity, therefore excellent filling properties, low brittleness, good adhesion, and does not peel off from the adherend. Known tin compounds that can be used in combination include (wherein R4 has 1 to 17 carbon atoms) R2/ゝ0OOR3 (In the formula, R2 is an alkyl group having 1 to 8 carbon atoms, and R3 is an alkyl group having 1 to +7 carbon atoms, an aryl group, or an alkylaryl group.) group or -OH= 0H-GOOR
4, R4 is an alkyl group having 1 to 18 carbon atoms (in the formula, R5 is an alkyl group having 1 to 8 carbon atoms, and R6 is an alkyl group having 2 to 18 carbon atoms). Among these, preferred are dibutyltin diacetate, dibutyltin dilaurate, dibutyltin bis(monolauryl malate), and dibutyltin dimercapto diurate. % by weight, preferably 0.1 to 10 weight,
Ling% used.

In producing polyurethane foam according to the present invention, it is of course necessary to use a substance that forms cells, and as is well known, such substances include:
Water, which reacts with the polyisocyanate to generate carbon dioxide, or a blowing agent, which does not participate in the polyurethane production reaction, is used. Any known blowing agent can be used, and preferably low-boiling halogenated hydrocarbons that are liquid at room temperature and vaporize during the polyurethane production reaction are used. Although the water and the blowing agent may be used alone, it is preferable to use both in combination.

In addition, in the present invention, the molecular weight is 32 to 40 as necessary.
It goes without saying that a polyfunctional compound of 0.0 may be used as a normal chain extender, and the properties of the polyurethane foam obtained can be adjusted as appropriate by using this chain extender.

In the present invention, it is preferable to use a surfactant during the production of polyurethane foam to improve cell uniformity and cell retention. Silicone-based surfactants are mainly used as such surfactants;
A nonionic material that does not contain fluorine is used in combination as appropriate.

Hereinafter, the present invention will be explained in more detail with reference to Examples. Note that parts in the examples are based on weight.

Example 1 Hydroxyl number 450 obtained by addition reaction of polypropylene oxide with a mixture of sucrose, ethanolamine and water. N%1.4.Viscosity at 25℃8000
Centiboise polyether polyol 100 parts, water s
, s part, silicone surfactant [Toray Silicon 8H-
193° Toray Silicon Co., Ltd.) t, S part, each part shown in catalyst Table 1, and 40 parts of -monofluorotrichloride methane (Freon JIB% Mikata Fluoro Chemical Co., Ltd.) were mixed. This mixture was reacted with crude [4,4'-diisocyane-)diphenylmethane [Sumidur 44v-20, Neo-containing i3D, 7%, Sumitomo Bayer Urethane Co., Ltd.] with isocyanate index (incyanate equivalent/isocyanate) to give an activity of 5. Hydrogen equivalent) = 1.05 was mixed under the same conditions in a rotor-stirring urethane foaming machine (mixer rotation speed 4.00 Or, p, m) and poured into the molds below.〇1) Cream time, gel time , tank free time/rise time, free firing density, firing? + 5tynX I 5cmX 5Q (
:A 0.03n+m polyethylene film is pasted on the inside of rn (height), and the vertical direction 2 is applied to the inside polyethylene wall.
1201 was injected from the foaming machine into a wooden mold with an open top and a stainless steel plate with a thickness of 0.5 m that had been degreased on the surface. The mold temperature, aluminum plate temperature, stock solution temperature in the foaming machine, and air temperature were all 25°C.

l) 41 cm (width) * 60 tw for measuring foam fillability (flowability) and low temperature dimensional stability of foam
o, os inside r (height) Xi5CrII (thickness)
280.9 g of the foam was injected from the foaming machine into a sealable aluminum mold to which a TNN polyethylene film was attached.

Mold temperature, stock solution temperature inside the foaming machine, and air temperature are all 25℃.
Met. Table 1 shows the results of measurements using the catalyst of the present invention and the known catalyst in reaction systems in which the same amount of addition and gel time were obtained.

In addition, in the catalyst name abbreviations in the table, TgDA is triethylenediamine, DMOA is N,N-dimethylcyclohexylamine, DMKA is N,N-dimethylethanolamine, DMBA is N,N-dimethylbenzylamine, and TIJHD is N,N. , f, N'-tetramethylhexamethylenediamine, PMDETA is N I N #"l button f-pentamethyldiethylenetriamine, 04 is formula
s n is 1 and 20 molar ratio 8:2 mixture, 06 is formula U
], R1 and R2 are 06H12, n is 1 and 20 molar ratio 7
:3 indicates a mixture O *1 Surface brittleness 202 Surface is not brittle ○: Cloth surface brittle for 10 minutes ×: Surface brittle for 10 to 30 minutes XX2 Surface brittle for more than 30 minutes *2 Odor : ◎: Weak ○: Slightly weak ×: Strong ××=Very strong *33-part properties: When the urethane foam and stainless steel plate are peeled off after 10 minutes of injection foaming 0: Strong adhesion ○: Slightly strong adhesion ×: Adhesion Weak resistance XX: Very weak adhesion *4 Low temperature dimensional stability: Mold ■) - (The foamed center part is l OCrn
Cut into ln - 20℃, z4nrffl dimensional change rate width) (maximum change part) *5 Fillability (%): Urethane foam volume when 2 soy is injected/molten volume in mold x 100 Example Same as Example 1 Using raw materials, the sweat distribution ratio was set to 100 parts of polyether polyol, 0.4 parts of water, and 1 part of silicone surfactant.
．． 0 parts, monofluorotrichloromethane 24 parts, catalyst coat 2
The parts shown in were mixed.

This mixture and crude 4. Put 14 kp of l-diincyanate diphenylmethane into a 20-e poly bucket at a ratio of isocyanate index of 1.05 and mix it with Kikusui auto mixer (MK-120 type 1, iris 00 r, p, m approximately 12 m after the blades, Usui Kagaku Kogyo Co., Ltd.) ] for 15 seconds at 90crnX 90crnX 50
It was poured into a wooden mold with a 0.03 mm polyethylene film pasted on the inside of the crn (height), and the mold was clamped using a 'g# press (manufactured by Hanako Seisakusho, mold clamping area Im x 2 m), and released after 60 minutes and 90 minutes. I molded it.

The dimensions of the molded product after demolding and the center of the molded product are 90 x 45 cm.
The internal state was observed by canting rn x 30 units.

In addition, a 0.03m+g polyethylene film was pasted on the inside of the same mold, and the polyether film (3.5nllIn
Set a thick degreased stainless steel plate, open the top of the mold and add the above mixture + OK! i was injected, and the cream time, gel time, tack free time, rise time, free foam density, surface brittleness after foam hardening, and adhesion to a stainless steel plate were measured. The mold temperature, raw material liquid temperature, and air temperature were all 20°C.

Table 2 shows the results of measurements of the catalyst system of the present invention and the known catalyst system in reaction systems with the same tank free time.

In addition, in the catalyst name abbreviation TEDA in the table, C6 is triethylenediamine, and R1 and R2 of formula (1) are C6H12.
, n is a 7:6 molar ratio mixture of 1 and 20, and 8n indicates dipterthene dimerkabuto 2 urate. - Dimensional change after demolding and burns on the crank and foam are shown on the left, and on the right is a product demolded for 60 minutes. is a product demolded for 90 minutes.

*1 Crank 202 complete (no abnormalities.Q * nl 1
There are 1 to 2 cracks with a length of 5 cm or less @x
: +lt There is a crank with a length of 1 to 3 mm and a length of 5 to 1 gtnm. X: There is a crack with an Ip of 3 m or more and a length of 10 or more.

*2 There is no change in the firing of form 202. ○: The center is very slightly yellowed. ×: The center is dark yellow or dark brown. ×X: The center is dark brown or blackish brown.

*5 Surface fragility: ◎: The surface is not brittle at all. ○: Cloth surface 7
Brittle for minutes. ×: The surface is brittle for 7 to 15 minutes. ×X: The surface is brittle for 15 minutes or more.

*4 Adhesiveness 202 If you try to peel it off, the stainless steel plate will deform. The stainless steel deforms and peels off. ×The stainless steel plate can be removed without deforming. XX = Stainless steel plate does not deform and can be easily peeled off.

Applicant's agent Kaoru Furutani

Claims (1)

[Claims] 1. A method for producing polyurethane foam from a compound having at least two active hydrogen atoms and having a molecular weight of 400 to 10,000, polyisocyanate, water and/or a blowing agent, which comprises the following general method. A polyurethane foam characterized by using a catalyst represented by the formula ' (R1 and R2 represent the same or different alkylene groups having 4 to 8 carbon atoms, and n represents a positive integer of 1 to 4) Manufacturing method.