JPS5849568B2 - Manufacturing method of hard urethane foam - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing rigid urethane foam with extremely low foaming pressure during foam production.

Rigid urethane foam has recently been used for a wide range of purposes, including insulation, building materials, and furniture materials due to its many excellent physical properties such as excellent heat insulation and excellent mechanical strength, as well as its versatility in processability.

However, in the conventional production of rigid urethane foam, extremely high foaming pressures are applied during foam generation, and in cases such as mold foaming of rigid urethane foam or injection foaming between wallboards, this high A major problem was how to deal with foaming pressure.

In the past, in order to solve these problems, the mold was made stronger, a stronger press was used, or the walls were significantly reinforced.

For this reason, a large amount of equipment was required and the workability was poor.

A froth foaming method was developed and put into practical use in order to reduce the foaming pressure during foam production, but the foaming pressure increased by about 4 to 10 times after injection of the urethane stock solution, which was insufficient.

The present invention was made with the aim of eliminating these drawbacks, and aims to develop a method for producing rigid urethane foam that reduces foaming pressure during foam production.

The present invention provides polyisocyanates, polyols, reaction catalysts,
When producing rigid urethane foam from foaming uniformity +4, foam stabilizers, and other additives, polyol components and blowing agent components are mixed with polyisocyanate components, polyols, reaction catalysts, foam stabilizers, and other additives. Therefore, when mixing the polyisocyanate component and the polyol component, without adding any low-boiling point compound that is liquid at room temperature as a blowing agent, a gaseous blowing agent with a boiling point of 5°C or less is mixed at room temperature to foam and harden. This is a characteristic feature.

The stock solution for producing urethane foam consists of a polyisocyanate component consisting of polyisocyanate, a polyol, a reaction catalyst,
It consists of a two-component system consisting of a polyol component mixed with a foam stabilizer and other additives, and a blowing agent component which is a blowing agent that is gaseous at room temperature with a boiling point of 5° C. or lower.

In the present invention, when mixing the polyisocyanate component and the polyol component, a gaseous blowing agent is mixed at room temperature with a boiling point of 5° C. or lower.

When foaming with a foaming machine, this foaming agent is mixed with the polyisocyanate component and the polyol component that are being pumped from the original tank for mixing and foaming before mixing the polyisocyanate component and the polyol component in a mixing chamber. /Or they may be mixed into the polyol, or may be mixed simultaneously in the mixing chamber, or the polyisocyanate component and the polyol component may be mixed in the mixing chamber and then mixed when being discharged.

That is, a certain amount of the blowing agent may be mixed between immediately before the polyisocyanate component and a certain amount of the polyol are mixed and until the discharge of the mixed liquid is completed.

Examples of foaming agents that are gaseous at room temperature and have a boiling point of 5° C. or less that can be used in the present invention include dichlorodifluoromethane, monochlorodifluoromethane, and dichlorotetrafluoroethane.

Normal temperature is usually between about 10°C and 30°C.

Water, which is normally used as a blowing agent for urethane foam, is not used in the present invention because it reacts with polyisocyanate and generates carbon dioxide gas, resulting in high pressure.

As the polyisocyanate, all commonly used polyisocyanates can be used.

Tolylene-2,4-diisocyanate, Tolylene-2
．． 6-diisocyanate and mixtures thereof, diphenylmethane-4.4'-diisocyanate, 3-methyldiphenylmethane-4. 4'-diisocyanates and their crude products are used.

Preferably, crude diphenylmethane-4,4'-diisocyanate is used.

The amount of polyisocyanate used is 1.0 to 1.2 times the chemical equivalent of the total amount of active hydrogen compounds.

Preferred polyols are polyether polyols, including polyether polyols using sucrose, sorbitol, glycerin, trimethylolpropane, pentaerythritol, hexanetriol, ethylenediamine, triethanolamine, and the like as initiators.

As the reaction catalyst, foam regulating agent, flame retardant, and other additives, all those commonly used in the production of urethane foam can be used.

According to the present invention, when a polyisocyanate component, a polyol component, and a blowing agent component are mixed and discharged, the mixed liquid is already in the form of foam, and after being discharged, the mixture is 1.5 to 2.5 times the same as the time of discharge.
Since the foaming reaction is completed by about twice the expansion, the foaming pressure becomes extremely low.

In the case of conventional rigid urethane foam used as a heat insulating material, the expansion rate until the foaming reaction is completed is about 20 to 40 times, and the foaming pressure is 0. 5 ~1. 0kg/c wisteria level,
When using the floss foaming method, the expansion rate is about 4 to 10 times,
While the foaming pressure is 0.2 to 0.7k/crm degrees, in the present invention, the expansion rate is about 1.5 to 2.5 times, and the foaming pressure is 0.
．． It will be as low as 1k/crit or less.

In the present invention, the foaming pressure during foam production is extremely low, so even when mold injection foaming, injection foaming into panels, injection foaming into walls, etc., it is possible to use a sturdy mold, a rigid press, or a sturdy mold. This is an extremely useful manufacturing method because it does not require any reinforcing means, eliminates the need for expensive equipment, and improves workability.

Comparative examples and examples will be explained below.

Comparative Example I Liquid A Crude diphenylmethane-4.4 Diisocyanate 108 parts Liquid B Glycerin-based polyol 100 (molecular weight 4
00) Silicone foam stabilizer (SH-193) 1 Foaming agent (trichloromonofluoromethane) 40 Amine catalyst (dimethylethanolamine) 1.2 Flame retardant (TCEP) 1 0 Liquid temperature
Solution A, Solution B 20℃ Cream time (CT) 60 seconds Rise time (RT) 160 seconds A of the above formulation
The two components of liquid and liquid B were mixed using a foaming machine, and then discharged and foamed to form a foam.

(Discharge amount: 4.5 @/frost in) As a result, the mixed liquid was in a liquid state and the volume expansion was 35 times when foaming was completed before being discharged.

The foaming pressure in mold foaming is 1. 0 kg/cri
It was about.

Also, the density of the obtained foam is 30kvfr? Met.

Comparative Example 2 Liquid A Crude diphenylmethane-4.4 diisocyanate 120 parts Liquid B Sucrose space polyol 40 Sorbitol base polyol 60 Silicone foam stabilizer (SH-193) 1.0 Flame retardant (
TCEP) 1 0 dimethylethanolamine 1.0 dibutyltin dilaurate
0.2H20 1.
0 Trichloromonofluoromethane 40 Liquid temperature A and B liquids 20℃ Cream time 30 seconds Rise time 160 seconds A of the above formulation
When the two components of liquid and liquid B were mixed, a total of 6 methane by weight was mixed in at the same time, and the mixture was discharged in the form of a floss and foamed to form a foam.

(Foam density: 28k/m3) The foam discharged in the form of floss further expanded about 6 times.

The foaming pressure in mold foaming was approximately 0.5k/c4.

Example 1 In the formulation of Comparative Example 1, the foaming agent of the B liquid was removed to obtain a B liquid.

When mixing A component and B component using a foaming machine, 2% of dichloromethane of the total discharge amount is mixed into the A liquid side, and A
The components and B component were mixed at a ratio of 100/100 and discharged and foamed.

(Discharge rate: 4.5 ky/min) As a result, the mixed liquid is discharged in the form of foam, and the discharged foam completes foaming and expands in volume by approximately twice as much until it hardens. Ta.

Foam foaming pressure is 0. It was 1 ky/c Haruka Majesty.

The foam density obtained was 9 2 @/m3.

Example 2 Components A and B with the same formulation as in Example 1 were prepared, and dichloromethane was increased to 40% of the total discharge amount as a blowing agent and mixed into the A liquid side. Ingredients 1.00/10
The mixture was mixed at a ratio of 0 and foamed.

(The discharge rate was 4.5 Ay/min.) The mixed liquid was discharged in the form of foam, and the discharged foam completed foaming and expanded in volume by about twice as much until it hardened.

Foam foaming pressure is 0. The resulting foam had a density of 60 kg/Ca.

Example 3 Components A and B of the same formulation as in Example 1 were prepared, dichlorodifluoromethane was prepared as a foaming agent in 8 portions of the total discharge amount, and 4 portions each were mixed into liquids A and B. The components and B component were mixed at a ratio of 10.0/100, and the mixture was discharged and foamed.

(Discharge rate: 4.5 k/min) As a result, the mixed liquid was discharged in the form of foam, but secondary expansion after discharge was only slight.

The foam foaming pressure was about 0.05 kti/crti, and the density of the obtained foam was 36 kti/m3.

Claims (1)

[Claims] 1. In producing rigid urethane foam from polyisocyanate, polyol, reaction catalyst, foam regulating IJ, and other additives, polyisocyanate or polyol, reaction catalyst, foam regulating IJ, and other additives are used. It consists of a polyol component mixed with a blowing agent component, and without adding any low-boiling point compound that is liquid at room temperature as a blowing agent, foaming of gas at room temperature with a boiling point of 5℃ or less is possible when mixing the polyisocyanate component and polyol component. A method for producing a rigid urethane foam, which comprises mixing an agent and foaming and curing the mixture.