JPS5829811B2 - Manufacturing method of lightweight polyurethane plastic - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing lightweight polyurethane plastics.

More specifically, the present invention relates to a method for producing a lightweight polyurethane plastic having uniform and excellent mechanical properties using microballoons and a foaming agent as a weight reducing agent.

Conventionally, as a rigid lightweight polyurethane, so-called rigid polyurethane foam, which is foamed with a foaming agent, is widely known for its excellent processability and physical properties.

Rigid polyurethane foams can be broadly classified into two types: very low density foams used primarily as insulation materials and relatively high density foams used as structural materials.

The latter, relatively dense foams are generally produced by pouring into pressure molds and curing under large foaming pressures.

The molded product thus obtained consists of a non-foamed high-density skin layer and a foamed low-density core, and has scales that faithfully reproduce the pattern on the inner surface of the mold, and has high surface strength. It is used to make sculptures, picture frames, doors, etc.

On the other hand, depending on the application, the non-uniformity of the structure due to the built-in foam with low mechanical strength can often become a weak point.

For example, it is currently not possible to obtain a molded product that is satisfactory for use in deep-sea parts, which require high pressure resistance, and for furniture, shoe inserts, etc., which require good nailing performance.

It is therefore an object of the present invention to provide a lightweight polyurethane plastic without a skin layer and having uniform and excellent mechanical properties, in particular improved compressive strength.

Yet another object of the present invention is to provide a resin composition for producing the lightweight polyurethane plastic that can be applied to many types of casting machines, has low viscosity, and has excellent moldability.

The above-mentioned object of the present invention and its mode of implementation will become clear in the description that follows, but as a result of extensive research in line with these purposes, the present inventors have developed the present invention, that is, a polyhydroxy compound and a polyhydroxy compound. Using an inocyanate compound in combination with a microballoon and a foaming agent, a plasticizer is added as needed.
They discovered that this could be achieved by adding catalysts and other additives to cure the material.

Lightweight materials made by mixing microballoons with various resins have recently been attracting attention from various quarters as new industrial materials, but by mixing microballoons with polyurethane resin,
It is not yet known that a lightweight body with high mechanical strength and uniform structure can be obtained by curing.

However, when microballoons are mixed in, the viscosity of the resin increases significantly, so there is a limit to the amount of microballoons that can be used to ensure uniform mixing and easy pouring into the mold. Hard to get.

Furthermore, normal pressure molding has the disadvantage that voids are likely to occur on the surface of the molded product.

On the other hand, relatively high-density rigid polyurethane foam, which is made lightweight using only a blowing agent, not only has the weaknesses mentioned above, but also has very high foaming pressure during molding, so it requires a corresponding amount of money to manufacture. It requires a mold, a jig that can withstand high pressure, and a large press, and has disadvantages such as having an adverse effect on the life of the mold, cost, etc.

Therefore, by using the microballoon of the present invention in combination with a blowing agent, the amount of microballoon used for weight reduction can be reduced, and the solvent effect of the blowing agent can also be expected, so that the increase in viscosity of the resin is small and as a result, Lower density is possible.

Furthermore, by using a foaming agent, the mixture foams appropriately.
Every corner of the mold can be completely filled, and surface voids are also reduced.

Moreover, the foaming pressure is low, which is not only advantageous in terms of manufacturing equipment and cost, but also combined with the pressure resistance of microballoons, prevents the formation of a skin layer, creates an overall uniform structure, and has excellent mechanical properties. A lightweight body with good physical properties can be obtained.

The vine polyhydroxy compounds used in the present invention include:
These include various polyether polyols, polyester polyols, polyols mixed with these polyols, and/or mixtures of these polyols and short molecular polyols used in the production of rigid polyurethane foam.
Average molecular weight 200-1000. Those having an average number of functional groups in the range of 2 to 6 are useful.

The polyisocyanate compounds used in the present invention have two or more isocyanate groups in the molecule, such as tolylene diincyanate, polyphenylmethane polyisocyanate, diphenylmethane diisocyanate, heat-modified diphenylmethane diisocyanate, and 1.6 hexane diisocyanate. There are methylene diisocyanate, inphorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, and adducts and prepolymers with terminal incyanate groups obtained by reacting these polyisocyanates with active hydrogen-containing compounds, and these may be used alone or in combination.

Examples of microballoons that can be used in the present invention include resin microballoons such as phenol microballoons (manufactured by UCC) and Saran microspheres (manufactured by DOW), inorganic microballoons such as shirasu balloons, silica balloons, glass balloons, and perlite. Balloons are available, but Saran microspheres are particularly useful.

The amount of these used varies depending on the type of microballoon used and the density of the lightweight body required, but generally it is 0.5-5.0% based on the total amount of the polyol component and isocyanate component described below. Weight percent ranges are preferred.

The blowing agents used in the present invention include those known in the polyurethane foam field, such as water and low-boiling aliphatic halogen compounds such as trichloromonofluoromethane and methylene chloride, either alone or in combination.

The amount used is variable, but in the case of water it is within the range of 1.0% by weight or less based on the total amount of the polyol component and isocyanate component described below, and in the case of other low-boiling substances, it is also based on the total amount above. A range of 5-10 weight percent is preferred.

Examples of plasticizers that can be used in the present invention include ester plasticizers such as tricresyl phosphate, dibutyl phthalate, and dioctyl adipate, aromatic plasticizers such as alkyl biphenyl, and phenolic plasticizers.

As the catalyst that can be used in the present invention, catalysts known in the field of polyurethane foam can be employed.

For example, triethylenediamine, triethylamine,
These include amine catalysts such as N-methylmorpholine and organometallic compound catalysts such as diptyltin dilaurate and stannous octoate, which may be used alone or in combination.

Other additives used in the present invention include cell stabilizers and surfactants to control foam and improve compatibility;
Pigments and dyes for coloring, glass fibers and vinylon fibers for reinforcement and modification, various extender pigments, flame retardants, etc. are used as necessary.

Microballoons, blowing agents, plasticizers, etc. may be mixed with polyhydroxy compounds and polyisocyanate compounds during the production of the lightweight polyurethane plastic, but
It is preferable to mix it into the polyhydroxy compound in advance.

(Hereinafter, this mixture will be referred to as the polyol component) Of course, if the microballoons, blowing agent, plasticizer, etc. used do not have active hydrogen, they may be mixed in advance into the polyisocyanate compound as necessary.

(In this case, this mixture is referred to as the isocyanate component.

) In the present invention, the lightweight polyurethane plastic is
A polyisocyanate compound (or isocyanate component) and a polyhydroxy compound (or polyol component) with an incyanate group to active hydrogen (determined by Tselevitinov method) ratio in the range of 0.8/1.0 to 1.5/1.0.
It can be obtained by mixing at room temperature or with slight heating.

In this case, they are mixed in a casting machine or manually and poured into a mold.

The mold may be heated at room temperature or preheated to 80°C.

Here, the effects of the present invention are that since microballoons and a foaming agent are used together as a weight reducing agent, a significant increase in the viscosity of the resin is prevented, the moldability is excellent, the structure is uniform even in large molded products, and the mechanical properties are excellent. A lightweight polyurethane plastic having the following characteristics is obtained.

Therefore, the plastics are useful in fields where mechanical strength is required, such as deep-sea parts and various structural materials.

Hereinafter, specific embodiments of the present invention will be explained with reference to Examples, but the present invention is not limited thereto.

Example 1 Glycerin propylene oxide adduct (hydroxyl value 2
90) Mixed polyol (average molecular weight 430, average functional group number 3.5) consisting of 50gr, 25gr adduct of propylene oxide of ethylenediamine (hydroxyl value 780), and 25gr diptylphthalate (average molecular weight 430, average number of functional groups 3.5), 0.05gr water.
, dispersant (silicone L-5340, manufactured by Nippon Unica) 3
gr and Saran microspheres (XD- manufactured by DOW)
7051-04) Add 2gr and mix thoroughly.

The viscosity of this mixture was 32000 cps at 20°C.

Next, polyphenylmethane polyisocyanate (Millionate MR0 manufactured by Nippon Polyurethane) 85 was added to this mixture.
Add gr, mix at room temperature, 200X100X50
It was poured into a mm-sized aluminum mold and cured at room temperature, removed from the mold after 20 minutes, and aged for 3 days at room temperature. The density and compressive strength were measured according to ASTM D792 and D-695. Density: 0. 50? /crA compressive strength
; 280 kg/crtt.

The cut interior had a uniform structure without a skin layer.

(In general, in the case of rigid polyurethane foam using only a blowing agent, the density is 0.50?/cti and the compressive strength is 50-
(approximately 100 kg/c77f) Example 2 Density and compressive strength of lightweight bodies obtained in Example 1 by changing the amount of water added and setting the ratio of incyanate groups to active hydrogen groups to 105:1 and O. The measured values are shown in Table 1.

The interiors of these lightweight bodies all had a uniform structure.

Example 3 In Example 1, modified diphenylmethane diisocyanate (Millionate MTL1 manufactured by Nippon Polyurethane) 95 was used instead of polyphenylmethane polyisocyanate.
The lightweight body was obtained in the same manner as in Example 1 except that the same procedure was used as in Example 1. The lightweight body had the same physical properties as in Example 1 and had a uniform internal structure.

Example 4 In Example 1, the amount of Saran microspheres used was reduced to 1.5 gr, and instead of polyphenylmethane polyinsyanate, tolylene diinocyanate (T-
80, manufactured by Nippon Polyurethane) 54 gr, and otherwise obtained in the same manner as in Example 1. The lightweight body had a density of 0.50 P/i and a compressive strength of 300 kg/ctyf.

It had physical properties and a uniform internal structure.

Example 5 100 gr of mixed polyol used in Example 1
A lightweight body obtained in the same manner as in Example 1 except that 1.9 gr of Saran microspheres and 25.0 gr of glass balloons were added thereto had a density of 0.42 r/CrI.

Compressive strength: 380 kg/crj.

It had physical properties and a uniform internal structure.

Example 6 In Example 1, 0.2 parts by weight of water, 3,0 parts by weight of silicone L5340, and 2.2 parts by weight of Saran microspheres were added to 100 parts by weight of the mixed polyol used in Example 1, and the mixture was thoroughly mixed to form a polyol component. shall be.

On the other hand, 1.6 parts by weight of Saran microspheres were added to 90 parts by weight of Millionate MR and thoroughly mixed to form an incyanate component.

Next, a two-component low-pressure polyurethane casting machine (EA-2
05 type, manufactured by Toho Kikai), the polyol component/isocyanate component was mixed at a ratio of 100/87 (weight ratio) (
The lightweight body obtained at 3000 rpm had physical properties of density: 0.35 g/- compressive strength: 150 kg/crA, and had a uniform internal structure.

Example 7 80 gr of polyester polyol (average molecular weight 800, average functional group number 2.5) obtained by polycondensing ethylene glycol, trimethylolfuropane, and adipic acid, 10 gr of trimethylolpropane, and 30 gr of dibutyl phthalate.
Mixed polyol [average molecular weight 450. Average number of functional groups 275) Saran microspheres 2 in 100 gr
．． Add 4gr.

Meanwhile, trichloromonofluoromethane was added to 85 gr of polyphenylmethane polyisocyanate.

Next, the polyol component and the incyanate component were mixed at a ratio of incyanate group to active hydrogen of -1.1/1.0, and the physical properties of the lightweight body obtained in the same manner as in Example 1 were determined. Shown in Table 2.

Claims (1)

[Claims] 1. A method for producing lightweight polyurethane plastic, which comprises using a polyhydroxy compound and a polyisocyanate compound in combination with microballoons and a foaming agent, and curing the mixture by adding a plasticizer, catalyst, and other additives as necessary.