JP2821488B2 - Release agent - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a release agent, particularly to a release agent used in the production of a molded product of a polymer substance such as a synthetic resin or rubber.

2. Description of the Related Art As a release agent for a molded product, a liquid in which silicone oil, uncrosslinked wax, or the like is dissolved or dispersed in an organic solvent or an aqueous medium has been used. However, silicone oil causes repelling of paint.Therefore, when painting after release, or when there is a painting line adjacent to the molding line, the repelling or painting of silicone oil comes from the release agent. It has the disadvantage of causing poor adhesion of the film. Therefore, wax-based release agents are often used.

On the other hand, the uncrosslinked wax-based release agent has low durability,
The number of times of release by one application is about 1 to 2 times, and a release agent must be applied every molding cycle, which has a disadvantage of poor workability.

Problems to be Solved by the Invention The present invention has no effect on coating of a molded product, reduces the number of times of release agent application work performed in each molding cycle, and improves workability and durability. The purpose of the present invention is to provide a releasing agent that can be used.

Means for Solving the Problems The present invention relates to a release agent containing a crosslinking wax prepared by a crosslinking treatment with radiation, an organic peroxide or oxygen or an oxygen-containing gas.

The crosslinked wax used in the present invention may be a known wax, for example, a synthetic wax such as a polyethylene wax or a polyvinyl ether wax, or a petroleum wax such as a paraffin wax or a micro wax. By subjecting it to a crosslinking treatment with an oxygen-containing gas.

A particularly preferred crosslinking treatment is a treatment for slowly crosslinking a raw material wax, preferably a molten wax, using an oxygen-containing gas such as oxygen or air. In this case, the processing conditions such as the temperature and time of crosslinking and the supply amount of oxygen or oxygen-containing gas may be appropriately selected depending on the type and molecular weight of the raw material wax, the release performance of the release agent, and the like, and are not particularly limited. However, the crosslinking rate defined by the acid value (KOHmg) / oxidation time (hour) of the crosslinked wax is 0.0001 to 1.5, particularly 0.1 to
0.5 is preferable, and when it is 1.5 or more, since the oxidation reaction takes precedence over the crosslinking reaction of the raw material wax, the release performance of the release agent tends to decrease.

Further, the acid value of the cross-linked wax is preferably 0.3 to 15, particularly 0.5 to 3.0, if it is 0.3 or less, the cross-linking becomes insufficient, the release performance is not sufficiently improved, and if it is 15 or more, the processing time becomes longer. It tends to be longer and the release performance tends to decrease. In addition to the crosslinking treatment of the present invention, for example, a polar group may be further introduced by a usual oxidation treatment for the purpose of improving emulsifying properties.

The release agent according to the present invention is prepared by dissolving or dispersing the crosslinked wax obtained as described above in an organic solvent or an aqueous medium. The solubility of the crosslinked wax in an organic solvent is generally higher than that of the raw material wax, which is advantageous in preparation. This is presumably because, when a crosslinked structure is introduced into the wax, the content of low molecular components in the wax increases due to a cutting reaction that occurs simultaneously with the crosslinking reaction.

The crosslinked wax is usually used by dissolving or dispersing 0.5 to 40% by weight, preferably 0.5 to 10% by weight in a solvent. When the concentration of the crosslinked wax is 0.5% by weight or less, sufficient releasability cannot be exhibited, and when the concentration is 40% by weight or more, it is uneconomical.

Examples of the organic solvent include naphtha, mineral spirit, petroleum ether, cyclohexane, petroleum solvents such as n-hexane, benzene, toluene, aromatic solvents such as xylene, methylene chloride, 1,1,1-trichloroethane,
Tetrachlorodifluoroethane, 1,1,2-trichloro-
Examples thereof include halogen-based solvents such as 1,2,2-trifluoroethane, and the like, and these solvents may be used in combination of two or more if desired.

Further, as the aqueous medium, water and, for example, water and
Examples thereof include water-soluble polar solvents such as methanol, ethanol, acetone, and tetrahydrofuran, and mixtures thereof.

The release agent according to the present invention may have various kinds of cationic, anionic or nonionic surfactants, fluororesin powder, silicone oil, silicone wax, fluorine for the purpose of improving stability and wettability as required. A system surfactant may be appropriately added.

The release agent according to the present invention is particularly suitable as a release agent for molded articles such as various synthetic resins, for example, polyurethane, epoxy resin, polycarbonate, and various rubbers, for example, synthetic rubber, chloroprene, and fluororubber. It is.

Further, the release agent according to the present invention can also be used as a water repellent treatment agent, a waterproof treatment agent, a lubricant, a polishing agent and the like for fibers, paper, building materials and the like.

Action A feature of the present invention resides in the use of a wax having a crosslinked structure. Although the mechanism of action is not clear, the cross-linking structure introduced into the wax increases the film strength of the release agent film formed on the mold and the adhesion to the mold, demonstrating excellent release performance. It is thought that. In addition, when introducing a crosslinked structure into the wax by slow crosslinking treatment with oxygen, a polar group introduced by an oxidation reaction that occurs simultaneously with the crosslinking reaction improves the affinity between the mold and the release agent film on the mold surface. It is thought to exert an auxiliary effect. However, a conventional oxidized wax merely having a polar group introduced therein does not show such a remarkable effect.

 Hereinafter, the present invention will be described with reference to examples.

Examples 1 to 8 Polyethylene wax (average molecular weight: about 2500, melting point: 4
Crosslinked waxes 1 to 8 were prepared using 1 kg of polyvinyl ether wax (average molecular weight: about 3000, melting point: 45 to 48 ° C.) or 1 kg of a raw material wax according to the conditions shown in Table 1.

¹³ C-NMR spectrum (67.94 MHz) of the raw polyethylene wax and the crosslinked polyethylene wax 2 in the high magnetic field region
z; CDCl ₃ ; room temperature) are shown in FIGS. 1 and 2, respectively.
In FIG. 2, A (42.8 ppm), B (37.5 ppm) and C (24.8 ppm and 23.9 ppm) respectively show the spectra of the carbon at the cross-linking point in the alkyl chain and its α-position carbon and β-position carbon.

Release agents 1 to 9 were prepared by dissolving crosslinked waxes 1 to 8 in cyclohexane at a concentration of 4% by weight.

Comparative Examples 1 to 3 The untreated polyethylene wax or polyvinyl ether wax used in the above examples was dissolved in cyclohexane at a concentration of 4% by weight to release agent 1 '.
Or 2 'was prepared.

Further, a release agent 3 'was prepared by dissolving the crosslinked wax 1' prepared according to the conditions shown in Table 1 in cyclohexane at a concentration of 4% by weight.

Release performance test One of the release agents 1 to 9 and 1 'to 3' prepared in the above Examples and Comparative Examples was placed in an aluminum cup [45].
mmφ (lower diameter) × 62 mmφ (upper diameter) × 45 mm (depth)], and the cup was stored in a dryer (50 ° C.).

On the other hand, immediately after stirring and mixing the polyurethane raw material according to the following formulation, the polyurethane raw material is poured into the cup, a drawing pin is set up, and the polyurethane raw material is heated to 50 ° C. in a dryer.
For 5 minutes by foaming: blending components (parts by weight) EP-330N ¹⁾ 100 ethylene glycol 8 L = 3601 ²⁾ 1 MINICO L-102 ³⁾ 1.2 freon 11 16 MDI-PM-33 ⁴⁾ 51.1 1 ) Polyol manufactured by Mitsui Toatsu Chemical Co., Ltd. 2) Foam stabilizer manufactured by Nippon Unicar Co., Ltd. 3) Catalyst made by Active Materials Chemical Co., Ltd. 4) Isocyanate manufactured by Mitsui Toatsu Chemical Co., Ltd. After measuring the load, repeat the above test without applying a release agent to the inside of the cup,
The number of times of release until the weight reached kg or more was determined, and the results are shown in Table 2.

EFFECT OF THE INVENTION The release agent according to the present invention reduces the number of application of the release agent by producing excellent release properties and release sustainability when producing a molded product of a polymer such as a synthetic resin or rubber. Improve workability. In addition, the use amount of the release agent with respect to the production amount of the mold product is reduced, and the economy is improved. Furthermore, if the number of times the release agent is applied is reduced, dirt on the mold is reduced, and the number of times the mold is cleaned is also reduced, thereby improving productivity.

[Brief description of the drawings]

FIGS. 1 and 2 are high-field region of the raw material polyethylene wax and cross-linked polyethylene wax 2 respectively ¹³
1 shows a C-NMR spectrum. In FIG. 2, A, B and C show the spectra of the carbon at the cross-linking point in the alkyl chain and the carbon at the α-position and the carbon at the β-position, respectively.

Continuation of front page (72) Inventor Nobuhiko Taniiri 1-1, Oikecho, Kosai-cho, Koga-gun, Shiga Prefecture Neos Co., Ltd. (56) References JP-A-62-119010 (JP, A) JP-A-1-258914 (JP) , A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B29C 33/58 B22C 3/00 C10M 1/00-177/00

Claims (3)

(57) [Claims] 1. A release agent containing a crosslinked wax prepared by a crosslinking treatment with radiation, an organic peroxide or oxygen or an oxygen-containing gas. 2. The release agent according to claim 1, wherein the crosslinking rate in the crosslinking treatment with oxygen or an oxygen-containing gas is 0.0001 to 1.5. 3. The release agent according to claim 2, wherein the acid value of the crosslinked wax is 0.3 to 15.