JP5728256B2 - Panel manufacturing method - Google Patents

Description

  The present invention relates to a method for producing a rigid polyurethane sandwich panel in which face materials are integrally formed on both sides.

  A lower surface material and an upper surface material are disposed between the upper and lower heat plates of the press, and a frame material is disposed between the lower surface material and the upper surface material to form a cavity corresponding to the size of the panel. A method for producing a panel comprising a rigid polyurethane foam sandwich panel in which a stock solution composition for forming a polyurethane foam is supplied and foam-cured to laminate a front material and a back material has been generally used and is well known.

  In the manufacture of the above panel, after the stock solution composition is supplied to the cavity, the stock solution expands into the cavity while foaming, and therefore the gas in the cavity needs to be discharged. It is known to provide a hole for exhaust in the body (Patent Documents 1 to 6, etc.).

  The inventions described in Patent Documents 1 and 2 both relate to a method for producing a rigid polyurethane foam panel using pentane as a foaming agent, and supply the stock solution composition after replacing the inside of the cavity with nitrogen. The purpose of these inventions is to prevent the surface material or back material from swelling or coming off due to the internal pressure of the panel, and it is sufficient that the nitrogen in the cavity is simply discharged according to the foaming of the stock solution. The size of the hole is not a problem.

  The invention described in Patent Document 3 provides a method for producing a rigid polyurethane foam panel which uses a flexible face material in the production of a panel having an intermediate frame material and does not cause wrinkles of the face material at the end portion. It is characterized in that the composition is supplied in two parts. In addition, the invention described in Patent Document 4 is characterized by a mixing head device which is an inexpensive device and makes it difficult to generate stable discharge patterns and disturb the flow at the beginning of discharge. Although it relates to the manufacturing method, it is only necessary that the gas in the cavity be discharged, and a groove is formed as a vent hole in the connecting portion (corner portion) of the vertical and horizontal frames.

The invention described in Patent Document 5 also relates to a method for producing a rigid polyurethane foam panel using pentane as a foaming agent. By using pentane that is flammable and requires careful handling, the quality and production efficiency are improved. A method for manufacturing a heat insulation panel that is designed to provide an injection hole for a stock solution composition at a plurality of locations on one side of a frame material, and to specify a dimension between adjacent injection holes. One or a plurality of vent holes are provided in the central part between them.

The invention described in Patent Document 6 is a method of manufacturing a sandwich panel of water foam or carbon dioxide foamed rigid polyurethane foam, in which bubbles come into contact with a metal surface material or back material such as a color steel plate or an aluminum plate constituting the sandwich panel. In order to solve the problem of blistering on the face material of the sandwich panel, resulting in poor appearance, it is characterized by providing a gas guiding path at the injection port of the raw liquid composition together with the gas venting hole. is there.

  However, in the manufacture of water-foamed rigid polyurethane foam sandwich panels, simply providing a vent hole can prevent foam shrinkage at the corners, even if problems such as swelling at the center and detachment of the face material can be avoided. As a result, it was found that appearance defects occurred.

JP 2009-101561 A JP 2006-110903 A JP 2007-55236 A JP 2006-282726 A JP 2006-44181A JP 2008-137268 A

  In view of the above-mentioned problems of the known technology, the present invention has good surface smoothness at the center of the panel surface, can prevent dents (so-called sinks) due to shrinkage of the foam at the corners, and causes poor appearance. It is an object of the present invention to provide a method for producing a preventable rigid polyurethane sandwich panel.

The present invention provides a stock solution composition for forming a rigid polyurethane foam in a cavity formed by a lower surface material, an upper surface material, and a frame material disposed between the lower surface material and the upper surface material, and foam-cured. A method for producing a panel comprising a hard polyurethane foam panel in which a front material and a back material are laminated,
The gel time (Tg) of the stock solution composition and the filling time (seconds) in which the stock solution composition is foamed after being supplied to the cavity and filled into the cavity (Tf) satisfy the formula (1),
2 ≦ Tg−Tf ≦ 15 (seconds) [Formula 1]
The just pack density (djp) of the rigid polyurethane foam and the filled foam density (dp) constituting the panel satisfy the formula (2),
110 ≦ 100 (dp / djp) ≦ 130 (%) [Formula 2]
Gas vent holes are formed in the vicinity of corner portions of the frame member, and the cross sectional area of the gas vent holes is 15 mm ² or more per corner.

  According to the manufacturing method of the above configuration, the surface smoothness of the center portion of the panel surface is good, and the depression due to shrinkage of the foam at the corner portion can be prevented, so that the rigid polyurethane sandwich panel does not cause the appearance defect. Can be manufactured. In the case of the present invention, unlike the case of Patent Document 6, it is not necessary to provide a gas guiding path at the inlet of the stock solution composition.

  When Tg-Tf is less than 2 seconds, the smoothness of the surface of the panel on which the face materials are laminated becomes insufficient, and when it exceeds 15 seconds, the surface of the panel is smooth and good. Occurs and becomes defective. When 100 (dp / djp) is less than 110%, the smoothness of the surface of the panel on which the face materials are laminated is insufficient, and when it exceeds 130%, the surface of the panel is smooth and good. After all, sink marks occur and become defective. In the case of water-foamed foam, if Tg-Tf exceeds 15 seconds, if 100 (dp / djp) exceeds 130%, sinking occurs in the corner. The shape is elongated in the direction parallel to the face material in the hole direction, and this is considered to be the main cause.

  The raw material which forms the rigid polyurethane foam which is the heat insulating material of the panel of the present invention is not particularly limited, and a stock solution composition in which a polyol composition containing a polyol compound, a foaming agent, a catalyst and the like and a polyisocyanate component are mixed and foamed and cured. Use as a thing. It is also possible to use a commercially available rigid polyurethane foam raw material for a panel in which a polyol composition and a polyisocyanate component are set. The foaming agent that forms the foam is preferably water-based, and can be used in combination with hydrofluorocarbons such as HFC-245fa and HFC-365mfc, and hydrocarbons such as pentane, but only water is used. It is preferable to do. The stock solution composition preferably has a gel time (Tg) of 40 seconds or more and 100 seconds or less, more preferably 80 seconds or less, and even more preferably 70 seconds or less.

  As the catalyst, a catalyst known in the technical field of polyurethane foam can be used. However, it is preferable to use a tertiary amine because the storage stability of the polyol composition is good. The gel time is adjusted by using a so-called resinification catalyst that promotes the reaction between the hydroxyl group of the polyol compound and the isocyanate group. The tertiary amine catalyst as such a resinification catalyst includes N, N, N ′, N′-tetramethylpropylenediamine, N, N, N ′, N′-tetramethylhexamethylenediamine, ethylene glycol bis (3 -Dimethyl) -aminopropyl ether, triethylenediamine and the like.

The gel time Tg when the stock solution composition is foam-cured is adjusted by the addition amount of the catalyst, particularly the addition amount of the resinification catalyst. Since it is common technical knowledge that the gel time decreases as the catalyst addition amount increases within the general addition amount range, for example, after selecting the type of catalyst, the addition amount is set at three levels and the gel time of the stock solution composition is measured. The range of 40 seconds or more and 100 seconds or less is obtained by repeating the operation of measuring the gel time at the addition amount in the range of 2 to 5 with the addition amount within the range including the range of 40 seconds or more and 100 seconds or less. Easy to set.

  FIG. 1 illustrates the rise curve of a rigid polyurethane foam. The rise curve is an approximately S-shaped curve with the horizontal axis representing the time from the completion of mixing of the polyol composition and the polyisocyanate component, and the vertical axis representing the foam foam height. Foaming progresses for a few seconds after the gel time, and the maximum foam The foaming and curing is finished at the height.

The filling time Tf is the time for closing the vent hole after the stock solution composition in progress of foam curing is filled in the molding cavity, and is measured visually. As described above, foaming proceeds for a few seconds after the gel time, and the stock composition expands in the cavity while foaming, but the amount of so-called foaming catalyst having an action of promoting the reaction between water and isocyanate groups is adjusted. Thus, Tg-Tf can be adjusted to a predetermined range. Although the resinization catalyst is weak, it acts as a foaming catalyst, and the foaming catalyst is also weak but acts as a resination catalyst. However, a typical foaming catalyst, a resination catalyst, has a foaming effect and a resinating effect of 10 times or more. There is a difference and it can be said that it is a separate catalyst. Therefore, by using the foaming catalyst and the resinification catalyst and adjusting the gel time as described above and then adjusting the addition amount of the foaming catalyst, Tg-Tf can be easily adjusted to a predetermined range.

Examples of the foaming catalyst include tertiary amines such as dimethylaminoethoxyethanol, bis (2-dimethylaminoethyl) ether, N, N, N ′, N ″, N ″ -pentamethyldiethylenetriamine.

  Just pack density (djp) is the density (free foaming density) when the undiluted liquid composition is poured into a mold having a square horizontal cross section and foamed without capping the upper surface to form a substantially cubic foam with a raised central part. It is the density of the foam which is obtained and calculated from the free foaming density using the mold that is actually used and foamed by supplying the stock solution composition that fills the mold 100%. Due to the resistance the stock solution composition receives from the mold during foaming, the foam cures without filling the mold 100%. Due to foaming in the closed cavity, the just pack density (djp) is usually higher than the free foam density. 100 × (dp / djp) (%) is generally referred to as a pack rate, and indicates how much of the stock solution composition is supplied with respect to the amount of the stock solution composition that is 100% filled into the cavity at the just pack density. is there.

The just pack density (djp) of the rigid polyurethane foam can be adjusted by the amount of water to be blended. (Dp / djp) can be set by adjusting the amount of the stock solution composition supplied to the molding cavity of the rigid polyurethane foam panel. That is, it can be achieved by supplying 1.1 to 1.3 times as much stock solution composition as the supply amount of the stock solution composition necessary to fill the volume of the molding cavity calculated from the just pack density. .

  The rigid polyurethane foam panel of the present invention has a rectangular shape and is used for building materials. The size is the size excluding the frame, preferably the length is 1 m or more and 3 m or less, and the width is 20 cm or more, preferably 40 cm or more, more preferably 50 cm or more and 2 m or less. The thickness is preferably 20 mm or more, preferably 30 mm or more and 150 mm or less. Preferred examples of the front and back face materials include craft paper face materials, aluminum laminated paper face materials, resin film laminated paper face materials, and paper face materials in which aluminum and a resin film are laminated. In addition, when used for floors or the like, hard face materials such as OSB, MDF, and thick plywood can be used on one side. The frame body may be formed integrally with the panel, or may be a panel made of only a face material and foam as separate materials.

  In the vicinity of the corner of the frame material, the center of the vent hole is within 5 cm from the corner (corner), preferably 4 cm or less, and more preferably 3 cm or less. If the center of the gas vent hole is too far away from the corner portion, air accumulation in the corner portion is likely to occur. The formation position of the vent hole may be on the long side or on the short side.

The cross-sectional area of the vent hole is 15 mm ² or more per corner, but the shape of the hole is preferably a round hole or a long hole. In the case of a round hole, the diameter is less than 7 mm, preferably 6.8 mm or less. . One or more vent holes may be formed per corner, and the total cross-sectional area may be 15 mm ² or more. The number of the vent holes is not particularly limited, but is preferably 3 to 4 or less from the processing man-hours. When providing a plurality of vent holes, the one farthest away from the corner is within 5 cm. If the cross-sectional area of the vent hole is too small, defects due to insufficient filling of the foam in the cavity and sink marks on the corners occur, and if too large, sink marks occur on the corners. The total cross-sectional area is preferably 80 mm ² or less, preferably 70 mm ² or less, and more preferably 60 mm ² or less.

  FIG. 2 shows an example of the injection position of the stock composition and the formation position of the vent hole in the panel molding. FIG. 2 (a) shows an example in which the stock solution composition is supplied to the center of the panel and the vent holes are formed near the long side end and near the short side end. ) Is an example in which the stock solution composition is supplied to the short side of the central portion in the width direction of the panel, and the vent hole is formed on the short side on the opposite side. The frame body 10 is composed of a long side frame body 13 and a short side frame body 15, the gas vent hole 17 is supplied, and the stock solution composition is supplied to the position 19.

In the present invention, the weight of the foam leaking from the vent hole is preferably set to 6 g / 1 corner or less. If the amount of leakage exceeds 6 g per corner, sink marks occur in the panel at the corner. The amount of leakage of the stock solution composition is determined by leaking from the vent hole after completion of foam hardening of the stock solution composition in panel production, cutting the cured foam and measuring the weight. The amount of leakage is 0 g, that is, more than the state where the cavity is 100% filled. If the amount of leakage exceeds 6 g per corner, sink marks are also generated at the corner. The stock solution leakage amount can be adjusted to 6 g or less by adjusting the cross-sectional area of the vent hole after adjusting the gel time, filling time, and packing rate. The degassing hole cross-sectional area may be subjected to a molding test from a small area, and when the leakage amount is less than 0, it may be gradually increased.

(Examples 1-4)
The same stock solution composition having a gel time of 50 seconds and Tg-Tf of 10 seconds was used, and a panel was produced under the condition of 100 (dp / djp) = 125% while changing the size and cross-sectional area of the vent holes. One or two degassing holes are formed. In the case of one, the center is formed at a position where the center is 4 cm from the corner portion, and in the case of two, the one far from the corner portion is formed at a position of 4 cm. The near ones were formed at positions where the outer periphery was 7 mm apart. The used mold had a cavity thickness of 10 cm, a width of 1 m, and a length of 2 m, and the stock solution composition was supplied to the position shown in FIG.

(Examples 5 and 6)
Using the same undiluted solution composition with a gel time of 50 seconds and Tg-Tf of 10 seconds, the size of the gas vent hole is 5.5 mm in diameter, each forming four round holes near the corner part, and the center part. The stock solution composition was supplied to the panel to form a panel under the condition of 100 (dp / djp) = 125%.
(Example 7)
Using a stock solution composition with a gel time of 50 seconds and Tg-Tf of 15 seconds, the size of the gas vent hole is 5.5 mm in diameter, each with four round holes near the corner, for a total of four in the center. The stock solution composition was supplied to form a panel under the condition of 100 (dp / djp) = 125%.

(Comparative Examples 1 and 2)
A panel was produced under the same conditions as in Example 7 except that a stock solution composition having a gel time of 50 seconds and a Tg-Tf of 0 seconds or a stock solution composition of 25 seconds was used.

(Comparative Examples 3 and 4)
The same stock solution composition as in Example 1 was used, and panels were produced with a pack rate (100 (dp / djp)) of 105% and 140%, respectively. In Comparative Example 3, four round holes with a diameter of 7.0 mm are formed in the vicinity of the corner part, and four round holes with a diameter of 5.5 mm are formed in the vicinity of the corner part in Comparative Example 4. A total of four each was formed.

(Comparative Examples 5 and 6)
The same stock solution composition as in Example 1 was used, and panels were produced with a pack rate (100 (dp / djp)) of 105% and 140%, respectively. In Comparative Example 3, four round holes with a diameter of 7.0 mm are formed in the vicinity of the corner part, and four round holes with a diameter of 5.5 mm are formed in the vicinity of the corner part in Comparative Example 4. A total of four each was formed.

  Table 1 summarizes the formulation of the stock solution compositions of Examples and Comparative Examples. The blending ratio is shown in parts by weight. The polyol compound Actol GR84 is a polyol (hydroxyl value: 450 mg KOH / g; manufactured by Mitsui Chemicals Polyurethane) with PO added with sucrose / glycerin as an initiator.

  The results of Examples and Comparative Examples are summarized in Table 2. In the evaluation, “◯” means “good”, “Δ” means slightly bad, and “x” means clearly bad. From the results shown in Table 2, Examples 1 to 7 of the present invention were all good in that the central portion of the panel had good smoothness of the double surface and there was no sink in the corner portion. On the other hand, Comparative Example 1 in which Tg-Tf is 0 second does not have sufficient surface smoothness without evaluating the corner portion, and Comparative Example 2 in which Tg-Tf is 25 seconds has a leakage amount of 8 g or more. The sink marks at the corners were bad and the product was defective. Further, Comparative Example 3 with a pack rate (100 (dp / djp)) of 105% is not sufficient in surface smoothness without evaluating the corner portion, and Comparative Example 4 with a pack rate of 140% has a leakage amount of 8 g or more. At the same time, the sink marks in the corners were bad and the product was defective. Comparative Example 5 using the same undiluted composition as in Example 1 and molded at the same packing ratio produced a defect of insufficient filling due to the small cross-sectional area of the gas vent hole, and the cross-sectional area of one gas vent hole was too large. In Comparative Example 6, the total cross-sectional area was not large, but the amount of leakage increased, so that the corner portion had sink marks.

Figure illustrating the rise curve of free foaming with the vertical axis representing the foam height and the horizontal axis representing time. The figure which showed the example of the injection | pouring position of stock solution composition in the shaping | molding of a panel, and the formation position of a vent hole

DESCRIPTION OF SYMBOLS 10 Frame 13 Long side frame 15 Short side frame 17 Gas vent hole 19 Stock solution composition supply position

Claims (4)

A stock solution composition for forming a rigid polyurethane foam is supplied into a cavity formed by a lower surface material, an upper surface material, and a frame material disposed between the lower surface material and the upper surface material, and foamed and cured to form a surface material and a back surface. A method of manufacturing a panel having a rigid polyurethane foam panel in which materials are laminated,
The gel time (Tg) of the stock solution composition and the filling time (seconds) in which the stock solution composition is foamed after being supplied to the cavity and filled into the cavity (Tf) satisfy the formula (1),
2 ≦ Tg−Tf ≦ 15 (seconds) [Formula 1]
The just pack density (djp) of the rigid polyurethane foam and the filled foam density (dp) constituting the panel satisfy the formula (2),
110 ≦ 100 (dp / djp) ≦ 130 (%) [Formula 2]
A method for manufacturing a panel, wherein a gas vent hole is formed near a corner portion of the frame member, and a cross-sectional area of the gas vent hole is 15 mm ² or more per corner.   The panel manufacturing method according to claim 1, wherein the vicinity of the corner portion of the frame member is within 5 cm from the corner portion.   3. The panel manufacturing method according to claim 1, wherein the gel time (Tg) is 40 seconds or more and 100 seconds or less. The method for manufacturing a panel according to claim 1, wherein the stock solution composition uses water as a foaming agent.

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