JP3057497B2 - Monomer cast nylon - Google Patents

Description

The present invention relates to a composition for monomer-cast nylon produced by monomer casting, and in particular, a product produced by the composition is subjected to a high load under high temperature. For example, it is suitable for use in materials such as rollers, pallets, liners, wheels, and guides.

(Problems to be solved by the prior art and the invention) Monomer cast nylon has excellent mechanical strength, but has a large difference in mechanical strength and elastic modulus at temperatures around the glass transition point. There is a disadvantage that excellent characteristics cannot be exhibited depending on the environment. That is, there is a problem that the strength surface and the thermal stability are lacking in a high temperature range of a glass transition temperature or higher.

Therefore, it is conceivable to improve the strength by mixing and dispersing the inorganic filler in the monomer cast nylon to form a cast product, but in this case, after the polymerization starts, before the viscosity of the raw material starts to increase In addition, there is a problem that the filler precipitates, so that the amount of addition is limited, and the expected effect is not exhibited.

In view of this background, monomer cast nylon that has excellent properties in terms of strength, etc., even in the high temperature range above the glass transition temperature, and can be used effectively even in applications subject to high temperatures and high loads under use conditions The appearance of products is desired.

(Means for Solving the Problems) The present invention solves the above-mentioned demand, and the gist of the present invention is to disperse needle-like crystals of wollastonite having a particle size of 200 to 400 mesh in a nylon monomer. And the wollastonite is 10 to 25 per 100 parts by weight of nylon produced by monomer casting.
The composition for a monomer cast nylon is characterized in that it is contained in a ratio of parts by weight.

Examples of the monomer cast nylon of the present invention include 6-nylon using ε-caprolactam as a raw material, 12-nylon using ω-laurolactam as a raw material, and the like.

The present invention uses such a nylon as a matrix, and disperses a specific amount of fine powder crystals of specific wollastonite (wollastonite) in the matrix. That is, wollastonite used here is a needle-like crystal, the particle size is 200 to 400 mesh, and such wollastonite is 10 to 25 per 100 parts by weight of matrix nylon.
It is included in the ratio of parts by weight. Wollastonite, which is an acicular crystal, has a specific gravity of 2.9, and a bulk specific gravity of about 0.86, which is small as an inorganic filler, and is well dispersed in ε-caprolactam and ω-laurolactam maintained at 130 to 170 ° C., and In addition to the manufacturing advantage that sedimentation is extremely small, needles are used, so that compression, bending strength and elastic modulus are greatly improved. Further, it does not inhibit the anionic polymerization reaction, which is advantageous for producing a monomer cast nylon product.

The wollastonite used in the present invention is selected from the range of 200 to 400 mesh (preferably 200 to 300 mesh). If it is smaller than 400 mesh, the total surface area of the particles becomes too large, the oil absorption increases, the fluidity of the nylon monomer decreases, and it is not possible to mix a filler so much that the effect of reinforcing the strength is obtained. Also, if the wollastonite particle size is larger than 200 mesh, the amount of precipitates in the mold at the time of mixing and stirring with the raw material monomer or at the time of casting increases, and even if a large amount of filler is filled, it is expected. Strength reinforcement effect is not obtained, and in the same product,
Variations in physical properties occur between the upper and lower parts of the product, which is not preferable as a product.

In addition, the grain size of wollastonite in the present invention is
The 200 to 400 mesh is substantially in the range of 200 to 400 mesh. For example, when processing with a 200 mesh sieve, a small amount (5% When about (about) remains on the sieve, and when processing with a 400 mesh sieve, it does not mean that what passes through this sieve is completely 0, but some that pass through a small amount (about 5%). It means that it may be. Here, the mesh refers to a mesh by a Tyler type sieve.

In the present invention, wollastonite is used so as to be contained in a ratio of 10 to 25 parts by weight based on 100 parts by weight of nylon of the matrix. If the amount is less than 10 parts by weight, the expected effect on the mechanical properties is not so high.On the other hand, if it exceeds 25 parts by weight, the amount settled when mixing with the monomer and in the casting mold is large. Large variations in physical properties at the top and bottom of the product, lacking product uniformity,
Not preferred.

The production of a monomer-cast nylon product using the composition of the present invention may be performed according to a conventionally known monomer casting method, except that wollastonite is added to the raw material monomer.

If wollastonite is mixed in advance in the raw material tank and the raw monomer and wollastonite are mixed in the raw material tank, there is a possibility of sedimentation in the raw material tank. Therefore, it is preferable to mix the two immediately before casting and cast.

(Example) Example 1 2 kg of anhydrous ε-caprolactam in a stainless beaker
And adjust to 140-160 ° C. To this was added 15 g of tolylene diisocyanate as a polymerization co-catalyst, and 400 g of wollastonite (trade name: Chemolit, manufactured by Maruwa Biochemicals Co., Ltd., manufactured by Maruwa Biochemical Co., Ltd., passed through 95% through a 300-mesh sieve) was heated to about 120 ° C. in advance. In addition, stir so as to be uniformly dispersed.

On the other hand, 1 kg of anhydrous ε-caprolactam is placed in another stainless beaker, 6 g of sodium hydride (63% oil) is added as a polymerization catalyst, 15 g of a heat stabilizer is further added, and the mixture is heated to 140 to 160 ° C.

Then, after mixing the above two and uniformly stirring the system, 15
It was cast in a mold at 0 ° C. to obtain a monomer cast nylon product in which wollastonite was dispersed.

Comparative Example 1 A monomer cast nylon product was obtained in the same manner as in Example 1 except that wollastonite was not added.

The plate-like resin (thickness) obtained in Example 1 and Comparative Example 1 above
15mm, width 300mm, length 400mm)
Test pieces having dimensions required for measurement were prepared, and the compression properties (compression strength and compressive elasticity at 5% deformation at a measurement temperature of 23 to 150 ° C) and bending properties (measurement temperatures of 23 to 150) were prepared by the following methods. Flexural strength and flexural modulus at 0 ° C) were measured. The compression characteristics were measured based on ASTM-D6951, and the bending characteristics were measured based on ASTM-D790, using an Instron universal testing machine as a testing machine. The resulting compression characteristic values are shown in Table 1, and the bending characteristic values are shown in Table 2.

The units of the numerical values in Tables 1 and 2 are kg / cm ² .

(Effect of the Invention) (A) In the composition for monomer-cast nylon of the present invention, by using wollastonite having a prescribed crystal form and particle size, it can be uniformly dispersed in a nylon matrix. It is now possible to obtain highly filled monomer cast nylon products.

(B) In the present invention, wollastonite having a blending amount defined in the above can be filled.
The compression and bending properties at 110 ° C have been dramatically improved, about 1.5 times that of unfilled monomer cast nylon products.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-60-188458 (JP, A) JP-B-43-13222 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 77/00 C08G 69/00

Claims (1)

(57) [Claims] 1. A wollastonite of a needle crystal having a particle size of 200 to 400 mesh is dispersed in a nylon monomer, and the wollastonite is 10 to 25 weight parts per 100 parts by weight of nylon produced by monomer casting. A composition for monomer-cast nylon, which is contained in a ratio of 1 part by weight.