JPS5949897B2 - Method for manufacturing polyurethane foam laminate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a polyurethane foam laminate with high interlayer bonding strength by spray foaming with good workability.

Polyurethane foam is a thermosetting plastic foam, and among them, rigid polyurethane foam is widely used as an industrial heat insulation material due to its excellent heat insulation properties.

When using polyurethane foam as a heat insulating material, there are two construction methods: one is to form a heat insulating layer by bonding a polyurethane foam material that has been formed into a predetermined shape to the part to be heat insulated, and the other is to directly apply the urethane raw material liquid to the part to be insulated. A typical method is to spray foam to form a polyurethane foam laminate. FIG. 1 shows a state in which a polyurethane foam layer 3 is formed by spraying and foaming the urethane raw material liquid from the spout 1 of a foaming gun onto the surface of a heat-insulating target part 2 without using a masking material or shielding device. ing.

In this case, irregularities 6 consisting of many small protrusions such as granules, so-called dust spray-like irregularities, are formed on the peripheral edges of the polyurethane foam layer 3 or on both ends 5 of the foam parallel to the scanning direction 4 of the blowout port 1 of the foaming gun. is formed. When a polyurethane foam layer 7 is directly formed on this highly uneven polyurethane foam layer 3 soil by spray foaming without using a masking material or shielding device as shown in FIG. It is extremely difficult to obtain good bond strength in the joint with the polyurethane foam layer 7 formed on the surface. As shown in Fig. 3, the normally foamed portion of the polyurethane foam layer forms fine cells 8 and is bonded with good bonding strength. As shown, coarse cells 10 are formed and bonded with weak bond strength. In this case, the bonding strength generally decreases to 1/2 to 1/4 of the bonding strength of a normally foamed part formed from the same raw material liquid and not including a surface area with significant dust spray-like irregularities. Therefore, when forming a polyurethane foam laminate, a construction technique that provides good bonding strength between the already formed polyurethane foam layer and the polyurethane foam layer that is additionally foamed on this layer becomes an important issue. ．． In order to improve the bonding strength between polyurethane foam layers, a method has conventionally been used in which the surfaces of the ends of the polyurethane foam layer or both ends of the foam parallel to the scanning direction of the foam gun nozzle are smoothed. It is.

This method generally involves the use of a masking material around the surface to be sprayed or the installation of a shielding device to remove dust spray-like substances during the spraying of the raw material solution. . However, if the method using the masking material 1 is used, work is required for attaching and removing the masking material, which results in extremely poor workability during construction. In addition, the method of installing a shielding device requires prompt removal of polyurethane foam attached to the shielding plate or frequent replacement of the shielding plate, so work efficiency during construction is extremely poor in this case as well.
In view of the above points, a polyurethane foam laminate with good bonding strength and strength is produced by directly spraying a urethane raw material liquid onto a polyurethane foam layer having small protrusions and depressions on the surface without the need for complicated processes. There is a need for technology to do this. The present inventors have previously invented and filed an application for a method for improving the interlayer bonding strength by spray foaming a urethane raw material solution having the same composition as the urethane raw material solution used in the present invention on the cut surface of polyurethane foam. However, this method (Patent Application No. 28909 of 1971) has the problem that the polyurethane foam layer must be cut in advance, which increases the number of work steps and deteriorates workability. be.

The present invention has been made in view of the above points, and involves spray foaming a urethane raw liquid containing a polyhydroxy compound, a polyisocyanate, a blowing agent, a foam stabilizer, a flame retardant, a catalyst, etc. to produce a polyurethane foam laminate. In this method, a polyurethane foam layer is formed by forming a urethane raw material solution, which is a mixture of multiple types of blowing agents with different boiling points, with small projection-like irregularities at the edges without using a masking material or shielding device. On top, masking material,
The object of the present invention is to provide a method for easily and quickly producing a polyurethane foam laminate having good bonding strength by repeating spray foaming without using a shielding device or the like.

Hereinafter, the configuration of the present invention will be explained based on FIGS. 5 to 7.

In the present invention, a urethane raw material liquid containing a polyhydroxy compound, an essential base phase of polyisocyanate, multiple types of blowing agents having different boiling points, a foam stabilizer, a flame retardant, a catalyst, etc. is used. This urethane raw material liquid is used as a masking material.
A polyurethane foam layer 3a is formed by spraying foam onto the surface of the heat-insulating target part 2 from the spout of a foaming gun without using a shielding device or the like. In this case, irregularities 6a consisting of many small protrusions such as granules, so-called dust spray-like irregularities, are formed on the peripheral edge of the polyurethane foam layer 3a or on both ends of the foam parallel to the scanning direction of the blowing port of the foaming gun. It will be done. Other polyurethane foam layers 3b, 3c, etc. are repeatedly formed so that the ends of this polyurethane foam layer 3a overlap each other in the lateral direction without using a masking material, shielding device, etc. to form a base layer. A polyurethane foam layer is manufactured, and further, on the surface of the polyurethane foam layer 3a, 3b, 3c... of this base layer,
A polyurethane foam laminate is manufactured by repeatedly forming polyurethane foam layers 11 in the lateral direction and upward direction without using any masking material, shielding device, or the like. The parts to be heat-insulated are not limited to horizontal surfaces, but also vertical surfaces,
It may be an inclined surface or any other surface. The normal foamed portion of the polyurethane foam layer is as shown in FIG.
As in the case shown in the figure, fine cells 8 are formed and the bond is bonded with extremely good bonding strength, and as shown in FIG. Cell 12 slightly larger than 8
are formed and bonded with good bond strength. This slightly large cell 12 is similar to the large cell 10 in the case of FIG.
It is significantly smaller than . Even if the surface has small protrusions and recesses, the bonding with good bonding strength is possible because the foaming start temperature of the foaming agent is different, so the foaming start time is different.
It is thought that this action causes foaming to occur in multiple stages and slows down the foaming speed. The blowing agent used in the present invention is methane dichloride difluoride (CCh
F2, boiling point -29.8℃), methane trichloride monofluoride (C
Cl3F, boiling point 23.8℃), ethane trichloride trifluoride (
Fluorinated hydrocarbons such as CCl2FCClF, boiling point 47.6° C.) are suitable, and a plurality of these are used as a mixture.

In the present invention, the total amount of the multiple types of blowing agents added is 5 to 40 parts per 100 parts of the polyhydroxy compound), and the addition ratio of the multiple types of blowing agents is 0.05 to 40 parts, respectively.
A range of 0.95 is preferred. The detailed combination and addition ratio of multiple types of blowing agents are desirably selected appropriately based on the properties required by the intended use of the polyurethane foam laminate, such as density and tensile bond strength. Since the present invention is configured as described above, the urethane raw material liquid prepared by mixing appropriate amounts of multiple types of foaming agents with different boiling points as foaming agents can be directly spray-foamed without providing a masking material or shielding device. , a polyurethane foam laminate having good bonding strength can be produced with excellent work efficiency, and is particularly suitable for forming a polyurethane foam laminate in on-site construction.

Examples and comparative examples of the present invention will be described below.

Example: Spray a urethane base liquid consisting of a polyhydroxy compound, polyisocyanate, phosphate flame retardant, silicone resin foam stabilizer, and a foaming agent consisting of a mixture of methane trifluoride and ethane trifluoride trichloride. A polyurethane foam layer is formed by foaming, and the urethane base liquid is sprayed onto the surface of the polyurethane foam layer, which has significant irregularities in the form of dust spray, at both ends of the foam parallel to the scanning direction of the foaming gun spout. This operation was repeated to form a polyurethane foam laminate as shown in FIG.

In the figure, 13 is a normal polyurethane foam layer that does not include a foam end, 14 is a foam end with a small projection-like uneven surface, and 15 is a polyurethane foam layer formed by spray foaming on the soil at the foam end. Form layer. Comparative Example 1 The urethane raw material solution used in Example 1 was replaced with only methane trichloride monofluoride, and the foaming agent was then sprayed and foamed to form small protrusions on the surface as shown in Figure 8. A polyurethane foam laminate V) was formed from a normal foam portion that did not include a foam end portion having irregularities.

Comparative Example 2 The urethane base liquid used in the example was replaced with only methane trichloride monofluoride as the blowing agent, and the urethane base liquid was spray foamed to form a surface as shown in Figure 9. A polyurethane foam laminate was formed that included foam edges with small protrusions.

The composition ratio of the blowing agent in Examples, Comparative Example 1, and Comparative Example 2 was
Shown in the table. Examples obtained as above, Comparative Example 1,
The interlayer bond strength and cell size of the polyurethane foam laminate of Comparative Example 2 were measured and compared.

The results are shown in Table 2. The evaluation points for the interlayer bonding strength and cell size are the parts indicated by chain lines E, F, and G in FIGS. 8, 9, and 10. As shown in Table 2, the interlayer bond strength in the foaming direction of the polyurethane foam laminates according to the examples of the present invention was determined by the urethane raw material solution using only methane trichloride monofluoride as a blowing agent, which is not according to the present invention. The interlayer bonding strength of the formed polyurethane foam laminate (Comparative Example 2) having foam edges with small protrusion-like irregularities on the surface was significantly increased, and the air bubbles on the foam edge surface were significantly increased. In terms of size (cell size), the polyurethane foam laminates in the examples of the present invention were different from ordinary polyurethane foam laminates (comparative The cell size is not significantly different from that of Example 1), which indicates that the present invention does not impede the foam end face on the foam properties such as heat insulation effect.

[Brief explanation of the drawing]

Figure 1 shows the structure without using masking materials or shielding devices.
An explanatory diagram showing the state in which a polyurethane layer is spray foamed on the surface of the heat-insulated part. Figure 2 shows the masking material. An explanatory diagram of a polyurethane foam laminate obtained by syspray foaming using a conventional method using a drying device or the like without cutting, and Fig. 3 is similar to Fig. 2 and is surrounded by a chain line circle A. FIG. 4 is an enlarged view of the part surrounded by a dashed line circle B in FIG. 2; FIG. Figure 6 shows the chain line circle C in Figure 5.
Figure 7 is an enlarged view of the area surrounded by the dashed line circle D in Figure 5, Figures 8, 9, and 10.
The figures are explanatory diagrams showing polyurethane foam laminates in Comparative Example 1, Comparative Example 2, and Example, respectively, with dashed line circles E and F.
, G indicate the evaluation points for interlayer bonding strength and cell size. 1... Foaming gun spout, 2... Part to be heat-insulated, 3,
3a, 3b, 3c...polyurethane foam layer, 4.
...Scanning direction, 5... Form end, 6, 6a...
Small projection-like unevenness, 7... polyurethane foam layer, 8
...Fine cell, 10...Coarse cell, 11...
Polyurethane foam layer, 12...slightly large cells,
13... Ordinary polyurethane foam layer without foam edges, 14... Foam edges having a surface with small projections and projections, 15... Foam edges formed by spray foaming on the foam edges. polyurethane foam layer.

Claims (1)

[Claims] 1 In a method for producing a polyurethane foam laminate by spray foaming a urethane raw material liquid consisting of a polyhydroxy compound, polyisocyanate, blowing agent, foam stabilizer, flame retardant, etc., multiple types of blowing agents with different boiling points are mixed. A urethane raw material liquid is sprayed onto a polyurethane foam layer formed with small protrusion-like irregularities at the edges without using a masking material or shielding device. A method for producing a polyurethane foam laminate, characterized by repeating spray foaming.