JP2005246670A - Mold release agent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold release agent used in hot-press molding. <P>SOLUTION: The mold release agent is used for a polyisocyanate binder for bonding a fine piece-like or fibrous base material comprising, for example, a lignocellulosic material and contains an amine compound as a mold release component. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a release agent. More specifically, this mold release agent is suitably used as an internal mold release agent when, for example, a lignocellulosic substrate is hot-pressure molded using a polyisocyanate binder.

Building materials and automotive parts are hot-press molded using lignocellulosic materials such as wood strips or wood fibers as a base material. As a binder for lignocellulosic materials, polyisocyanate binders have been used recently as a countermeasure against formaldehyde.
When a lignocellulosic base material is hot-press-molded using a polyisocyanate-based binder, adhesion to the hot platen occurs due to the excellent adhesiveness of the binder itself. Various mold release agents have been used to prevent this adhesion (see Patent Documents 1 to 5, etc.).
Further, as a mold release agent for polyurethane molded products, a compound obtained by compatibilizing a metal salt of an aliphatic carboxylic acid with a tertiary amine (Patent Document 6) or a certain acid metal salt together with a primary and secondary amine is prescribed. (Patent Document 7) is known.
Refer to Patent Documents 8 and 9 as techniques related to the present invention.

JP-A-8-34026 JP 2000-119626 A Japanese Patent Laid-Open No. 2001-271051 JP-A-9-286008 JP 11-42613 A JP-A-7-70429 EP 0 119 471 A2 JP-A-11-315154 JP 2001-123399 A

The internal mold release agent based on waxes cannot provide sufficient performance due to poor formation of a release layer on the board surface when there are many voids in the molded body (see Patent Documents 2 to 4, etc.). In addition, when a metal salt of a carboxylic acid that imparts a curing accelerating action to the isocyanate component of the binder is used, it affects the physical properties of the binder itself, so the practical range of addition amount is extremely narrow, and a mold release agent is used in the molded body. There are practical problems such as difficulty in uniform dispersion.
In addition, as shown in Patent Documents 1 to 5, the release agent for the latter is researched that the release agent for polyurethane molded products cannot be used as it is when hot press molding a substrate such as a grinocellulose type. It is clear from the development.

An object of the present invention is to provide a novel mold release agent used when hot pressing a strip-like or fibrous base material made of lignocellulose and other materials using a polyisocyanate binder. To do.
Another object of the present invention is to provide a release agent particularly effective when a hot mat is a wet mat formed by wet papermaking.

As a result of intensive studies on such a release agent, the present inventors have found that an amine compound becomes an effective release component and have completed the present invention.
That is, the present invention is a release agent for a polyisocyanate-based binder that bonds a base material, and is characterized by containing an amine compound as a release component.

Hereafter, each element of this invention is demonstrated in detail.
Base Material The shape and material of the base material are not particularly limited as long as they are bonded with a polyisocyanate binder and subjected to hot pressing.
The shape of such a substrate is generally a strip shape or a fiber shape.
A lignocellulosic material is used as the material of the substrate.
As the lignocellulosic material, one or more kinds of wood chips such as strand chips, dust chips and flake chips, plant fibers such as wood fibers, hemp and cotton, and rice husks can be used.
As the material of the base material, inorganic fibers such as rock wool, slag wool and glass wool, and synthetic fibers such as PP and PE can be used. Furthermore, inorganic fine pieces (powder) such as calcium carbonate, aluminum hydroxide, silicic acid, inorganic fine pieces such as perlite, obsidian foam, shirasu foam, glass foam, and mineral fine pieces such as mica. It can also be used.
The above base materials can be used alone or in combination of two or more.

Polyisocyanate binders Polyisocyanate binders include tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HMDI), xylene diisocyanate (XDI), isophorone diisocyanate (IPDI), poly Isocyanate compounds or isocyanate polymers such as methylene polyphenyl polyisocyanate (polymeric MDI) can be used.
The blending amount of the polyisocyanate binder is appropriately selected depending on the purpose and use of the board as a molded product, but it is preferable to blend 0.5 to 15% by weight with respect to the base material.

This polyisocyanate binder is mixed with the substrate as it is or in an emulsified state. As an emulsifier for the polyisocyanate binder, one kind of general anionic, nonionic and cationic surfactants or a mixture of two or more kinds can be used. Examples of such surfactants include fatty acid soaps, rosin acid soaps, alkyl sulfonates, alkyl benzene sulfonates, dialkyl aryl sulfonates, alkyl sulfosuccinates, polyoxyethylene alkyl sulfates, polyoxyethylene alkyl aryls. Anionic surfactants such as sulfates, polyoxyethylene alkyl ethers, polyoxyethylene alkyl aryl ethers, polyoxyethylene sorbitan fatty acid esters, oxyethylene oxypropylene block copolymers and the like can be mentioned.
The blending amount of the emulsifier is appropriately adjusted according to the kind, blending amount and use state of the binder, but is preferably 0.1 to 10% by weight with respect to the binder.

Amine compound It is considered that the amine compound accelerates the curing of the isocyanate component in the binder. That is, the isocyanate whose reaction has been accelerated by the amine compound has a reduced degree of polymerization and an adhesive force. Accordingly, the adhesiveness of the molded body to the hot pressing plate is lowered, and the molded body is easily released from the hot pressing plate. That is, this invention uses an amine compound as the main mold release component.
Excessive acceleration of the isocyanate reaction by the amine compound is not preferable because it affects the physical properties of the polyisocyanate binder. Accordingly, it is necessary to appropriately adjust the reaction promoting action of the amine compound on the isocyanate and the amount of use thereof.
In the case of the carboxylic acid metal salt of the conventional example, since the reaction promoting action for isocyanate is strong, it is necessary to strictly control the amount used, and it is not practical.
On the other hand, the amine compound is practical because it can adjust the reaction promoting action on isocyanate.

According to the study by the present inventors, when the total number of carbon atoms of the alkyl group bonded to the nitrogen atom of the amine compound is 6 to 25, it is practical for a molded body in which the base material is bonded with a polyisocyanate binder. It was found to be a useful release agent. That is, a suitable release performance can be secured without strictly adjusting the addition amount range.
If the total carbon number is less than 6, the reaction promoting action is strong, and there is a problem that it becomes difficult to achieve both board physical properties and mold release performance. If the total carbon number exceeds 25, the reaction promoting action is too weak and sufficient separation is achieved. There is a problem that mold performance cannot be obtained.
Furthermore, the total carbon number of the alkyl group couple | bonded with a preferable nitrogen atom is 8-25. Here, a hydroxypoly (oxyalkylene) group or an alkanol group can be used in place of the alkyl group.
Further, it is preferable to employ a tertiary amine as the amine compound. Since tertiary amines do not bind to polyisocyanate binders, effects can be obtained in a small amount as compared to secondary amines and primary amines, and practical release agents that do not require strict adjustment of the addition amount can be obtained.

Furthermore, in order to suppress the reaction promoting action of the amine compound on isocyanate, an acid compound can be used in combination. Thus, by using together an amine compound and an acid compound, a practical mold release agent that does not require strict adjustment of the addition amount can be obtained.
Examples of the acid compound include generally known acids such as acetic acid, formic acid, glycolic acid, propionic acid, caproic acid, caprylic acid, crotonic acid, citric acid, malic acid, glutamic acid and aspartic acid.

A base material, a polyisocyanate binder, a release agent of the present invention and necessary auxiliary agents are kneaded and formed into a board shape. The mold release agent of the invention and / or a mold release agent conventionally used (for example, a wax-type mold release agent) is applied to the contact surface of the molded body with the hot pressure plate, and the hot press molding is performed.
Moreover, a base material, a polyisocyanate binder, and the release agent of the present invention can be dispersed in water to form a slurry, and the papermaking product can be subjected to a hot-pressure treatment. Since this papermaking body contains a large amount of moisture, the temperature during the hot-pressure treatment is maintained at a relatively low temperature in order to prevent boiling of this water. The mold release agent of the present invention and / or the conventional mold release agent can also be applied to the contact surface of the papermaking body with the hot pressure plate.
Since the release agent of the present invention is easily dissolved in water, it can be sprayed to supply a uniform and minimum amount of the release agent to the contact surface of the hot-press plate of the sample.

Examples of the present invention and comparative examples will be described below.
A dust chip for particle board was prepared as a base material of lignocellulosic material, and a board-like sample having the following composition was obtained.
Compounding amount (parts by weight)
Chip 100
Polymeric MDI 7
Dispersant 0.014
Water 7
Mold release agent 0.0-1.5

Sumidur 44V20 manufactured by Sumika Bayer Urethane Co., Ltd. was used as the polymeric MDI as the polyisocyanate binder.
In the above, the polymeric MDI is mixed with the same amount of water and a dispersing agent (with respect to polymeric MDI 0.2%) and dispersed with a high-speed stirrer.

Under the conditions where an external release agent is used in combination, a wax release agent (a silicicant L-337 manufactured by Chukyo Oil & Fats Co., Ltd.) was applied to a coal plate under the following conditions before subjecting the sample to hot pressure treatment.
Application method: Air gun (pressure 0.5kg / m ³ )
Coating liquid amount: 50 g / m ³
Diluent concentration: 3 to 10 wt%
Temperature: room temperature

The conditions of the hot press treatment are as follows.
Setting density: 0.67 g / cm ³
Press size: 150 x 150 x 7.1 mm
Heating conditions: 180 ° C x 2 minutes

なお、表１（表２も同じ）において、離型性能の◎、○、×、××は次のようにして判断した。
◎：コール板と成形体の接着は全く無く、コール板の汚れも生じない。
○：コール板と成形体の接着は無いが、一部コール板の汚れが生じる。
×：コール板と成形体は部分的に接着しているが、成形体を剥がせる。
××：コール板と成形体は全面的に接着していて、成形体を剥がせない。 The results are shown in Table 1.

In Table 1 (the same applies to Table 2), the release performance ◎, ○, ×, and XX were determined as follows.
A: There is no adhesion between the call plate and the molded body, and no contamination of the call plate occurs.
○: There is no adhesion between the call plate and the molded body, but some of the call plate is stained.
X: The call board and the molded body are partially bonded, but the molded body can be peeled off.
XX: The call plate and the molded body are adhered to each other, and the molded body cannot be peeled off.

  From the results in Table 1, it was confirmed that amine compounds (particularly tertiary amines) exhibited excellent characteristics as internal mold release agents for lignocellulose bonded with a polyisocyanate binder.

Next, an example in which a hot pressing process is performed on a papermaking body using rock wool as a base material will be described.
First, a slurry having the following composition is prepared according to a conventional method.
Compounding amount (parts by weight)
Rock wool 100
Polymeric MDI 7
Dispersant 0.014
Water 1350
Then, after adding an aqueous polymer as a general flocculant, it is cleaned using Nutsche and filter paper. Suction dewatered with an aspirator to form a mat. Subsequently, the release agents of the examples and comparative examples are spray-coated on the upper surface of the mat. A wax release agent is applied to the coal plate in the same manner as in Example 1.
Then, the hot-pressure process was performed on the following conditions.
Setting density: 0.67 g / cm ³
Press size: 150 x 150 x 7.1 mm
Heating conditions: 120 ° C x 120 seconds

The results are shown in Table 2.

  From the results in Table 2, it was confirmed that amine compounds (particularly tertiary amines) exhibited excellent characteristics as mold release agents for inorganic fibers bonded with a polyisocyanate binder. Further, in this embodiment, sufficient release performance can be ensured even though the processing temperature at the time of the hot-pressure processing is as low as 120 ° C.

  As described above, it can be seen that the novel release agent of the present invention has excellent performance as a release agent for a strip-like or fibrous base material bonded with a polyisocyanate binder.

  The present invention is not limited to the description of the embodiments and examples of the invention described above. Various modifications may be included in the present invention as long as those skilled in the art can easily conceive without departing from the description of the scope of claims.

Claims (8)

A release agent for a polyisocyanate-based binder for bonding a base material, comprising an amine compound as a release component. 2. The mold release agent according to claim 1, wherein the total number of carbon atoms of the alkyl group bonded to the nitrogen atom of the amine compound is 6 to 25. 3. 2. The mold release agent according to claim 1, wherein the total number of carbon atoms of the alkyl group bonded to the nitrogen atom of the amine compound is 8 to 25. 3. 4. The mold release agent according to claim 2, wherein a part of the alkyl group is substituted with an oxyalkylene group or an alkanol group (the number of carbon atoms is the same). The mold release agent according to any one of claims 1 to 4, wherein the amine compound is a tertiary amine. 6. The mold release agent according to claim 1, further comprising an acid compound that neutralizes the amine compound. A board manufacturing method, wherein an amine compound is used as an internal release agent when a substrate is hot-press molded using a polyisocyanate binder. The manufacturing method according to claim 7, wherein the hot pressing forms a wet papermaking body.