JPH0320359A - Monomer cast nylon - Google Patents

Abstract

PURPOSE:To form a monomer cast nylon with excellent strength in a high temp. range at a glass transition temp. or higher by incorporating wollastonite with a specified particle size and a crystalline morphology in a nylon at a specified ration when a monomer cast nylon is prepd. CONSTITUTION:A monomer cast nylon formed by monomer casting is incorporated with 5-40 pts.wt. wollastonite with a particle size of 200-400 mesh and an acicular crystal dispersed in the nylon based on 100 pts.wt. nylon. As the monomer cast nylon, nylon 6 wherein epsilon-caprolactam is used as a raw material and nylon 12 wherein omega-laurolactam is used as a raw material are cited.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) This invention is applicable to monomer cast materials produced by monomer casting, especially those that are subjected to high temperatures and high loads, such as rollers, pallets, liners, and wheels. This invention relates to monomer cast nylon, which is suitable for uses such as guides. (Prior art and problems to be solved by the invention) Monomer cast nylon has excellent mechanical strength, but has a low glass transition point. There is a large difference in the strength and modulus of elasticity at different temperatures, and there is a disadvantage that excellent properties cannot be exhibited depending on the usage environment.
The problem is that it lacks strength and thermal stability at the lath transition temperature and higher temperatures. Therefore, it is possible to improve the strength by mixing and dispersing a m-free filler into monomer cast nylon and casting it, but in this case, after the start of polymerization and before the viscosity of the raw material starts to increase, However, there is a problem that the filler precipitates, which limits the amount added and does not produce the expected effect.

Considering this background, it has excellent properties such as strength even at high temperatures above the glass transition temperature.
The advent of monomer cast nylon that can be effectively used in applications that are subject to high temperatures and high loads under usage conditions! desired. (Means for Solving the Problems) The present invention solves the above-mentioned needs, and its main feature is a heptanomeric cast nylon produced by monomer casting.
Wollastonite in the form of acicular crystals with a particle size of 200 to 400 mesh is dispersed therein, and the wollastonite is contained in a proportion of 5 to 40 parts by weight per 100 parts by weight of nylon. It consists of monomer cast nylon. Examples of the monomer cast nylon of the present invention include 6-nylon made from ε-caprolactam and 12-nylon made from ω-laurolactam. The present invention uses such nylon as a matrix, and a specific amount of fine crystals of a specific wollastonite (wollastonite) is dispersed therein. That is, the wollastonite used here is of needle-like crystals, and the particle size is 200 to 400 mesh, and the wollastonite used here is 5 parts by weight per 100 parts by weight of the nylon matrix.
It is contained in a proportion of ~40 parts by weight. Wollastonite, which is a needle-shaped crystal, has a specific gravity of 2.9 and a bulk specific gravity of 0.8.
Around 6, which is small for a non-iso filler, 130-170
In addition to the manufacturing advantages of being well dispersed in C-cabrolactam and ω-laurolactam maintained at ℃ and with extremely little sedimentation, it also has the advantage of producing needle-shaped crystals, which significantly improves compressive strength, bending strength, and elastic modulus. It will be done. Furthermore, since it does not inhibit anionic polymerization reactions, it is convenient for producing heptanomer cast nylon. The wollastonite used in the present invention has a molecular weight of 200 to 400
Selected from a range of mesh (preferably 200 to 300 mesh). If it is finer than 400 mesh, the total surface area of the particles becomes too large, the amount of oil absorbed increases, the fluidity of the nylon monomer decreases, and it is not possible to mix in enough filler to have the effect of increasing strength. In addition, when the grain size of wollastonite becomes larger than 200 mesh, the amount of precipitates in the mold increases when mixing with the raw material mo/mer or during casting, and even when a large amount of filler is filled. However, the expected strength reinforcement effect was not obtained, and the physical properties of the upper and lower parts of the same product varied, making it undesirable as a product. Note that the particle size of wollastonite in the present invention of 200 to 400 mesh means that it is substantially in the range of 200 to 400 mesh. This does not mean that it passes through, but if a small amount (about 5%) remains on the sieve,
When processing through a 400 mesh sieve, this does not mean that the amount of material passing through the sieve is completely zero;
This means that a small amount (about 5%) may pass through. Note that the mesh here refers to a Tyler sieve. In the present invention, wollastonite is used in an amount of 5 to 40 parts by weight, preferably 10 to 25 parts by weight, based on 100 parts by weight of the nylon matrix. If this amount is less than 5 parts by weight, the expected effect on mechanical properties will be achieved, while if it exceeds 40 parts by weight, a large amount will settle when mixed with the monomer and in the casting mold. I don't like it. The monomer cast nylon of the present invention can be produced by following a previously unknown monomer casting method, except for adding wollastonite to the raw material monomer. When blending wollastonite, if you mix the raw material monomer and wollastonite in the raw material tank in advance, there is a possibility that they will settle in the raw material tank, so it is better to mix the two immediately before casting and then casting. <Example> Example 1 Anhydrous ε-cabrolactam 2k in a stainless steel beaker.
and adjust the temperature to 140-160°C.

Tolylene diisone hepnate 15 was added to this as a polymerization cocatalyst.
wollastonite (Mengen name Kesorit, manufactured by Maruwa Biochemical Co., Ltd., 95% passed through a 300 mesh sieve) 400.
Add and stir to disperse evenly. On the other hand, take 1 kg of anhydrous ε-caprolactam in another stainless steel beaker, add 6 g of sodium hydride as a polymerization catalyst (extractivity 63%), and add 15 g of heat stabilizer.
Add and heat to 140-160℃. Next, after mixing the above two and stirring the system uniformly, 15
Monomer cast nylon with wollastonite dispersed was obtained by casting into a mold at 0°C. Based on this, measurements were made using an Instron type universal testing rock as a testing machine. The resulting compression characteristic values are shown in the f51 table, and the bending properties are shown in the ttS2 table.
Shown in the table.

Note that the units of numerical values in Tables 1 and 2 are kg/C1.

Monomer cast nylon was obtained in the same manner as in Example 1 except for the following points. The plate-shaped resins obtained in Example 1 and Comparative Example 1 (thickness 1
5 Soso, width 3001111, length 400mm) were each cut to prepare test pieces with the dimensions required for measurement,
For these, the compression characteristics (measurement temperature 2
Compressive strength and compressive elastic modulus at 5% deformation at 3 to 150°C) and bending properties (bending strength and bending elastic modulus at measurement temperature of 23 to 150°C) were measured. Compression characteristics are A
Based on STM-D6951, bending properties are ASTM-D
? In 90, #2fi improved by 1.5 times and #1 step.

(Effect of the invention) (a) In the monomer cast nylon of the present invention,
By using wollastonite with a defined crystal morphology and particle size, we were able to uniformly disperse it in the nylon matrix, making it possible to obtain highly filled cast nylon.

Claims (1)

[Claims] (1) Monomer cast nylon produced by monomer casting, which has a nylon content of 200 to
A monomer cast characterized in that wollastonite in the form of acicular crystals with a particle size of 400 mesh is dispersed, and the wollastonite is contained in a ratio of 5 to 40 parts by weight per 100 parts by weight of nylon. Nylon.