JPS60115639A - Prefoamed particle of 1,2-polybutadiene resin - Google Patents

Abstract

PURPOSE:The titled particles which can produce, with good moldability, foamed moldings exhibiting excellent flexibility, cushioning properties, and recovery in compression, made by prefoaming a specified polybutadiene resin. CONSTITUTION:A mixture comprising 100pts.wt. crystalline syndiotactic 1,2- polybutadiene resin particles (A) having an intrinsic viscosity of 0.7 or higher and a density of 0.90-0.925g/cm<3>, about 100-500pts.wt. water (B), about 3- 50pts.wt. dispersing agent (D) (e.g. fine powders of aluminum oxide) is put in a closed vessel. The temperature is raised to the starting temperature - ending temperature of resin crystal melting by differential scanning calorimetry to impregnate the resin with the foaming agent. Then, the resin particles under pressure are discharged into a low pressure atmosphere to form prefoamed particles, preferably, having an average cell diameter of about 20-2,000mu, an average number of voids of about 300/mm.<2> or less, an expansion ratio of about 3-50, and an average particle diameter of about 1-20mm..

Description

Detailed Description of the Invention The present invention relates to a crystalline synnotactic 1,2-polybutanene resin (hereinafter referred to as 1,2-polybutadiene a (fat)) for producing a highly elastic foam molded product by in-mold molding. The present invention relates to pre-expanded particles comprising:

Foam molded products made using the so-called bead foam molding method, in which foamed particles of thermoplastic synthetic resin are filled into a mold, heated, re-foamed, and simultaneously fused together, are lightweight and loose. It has excellent properties such as 11j properties and heat insulation properties, and its molding method is suitable for mass production, so it is widely used in cushioning materials, packaging materials, heat insulation materials, building materials, etc.

However, the production of foam molded products using the conventional bead foaming method is limited to products made from polystyrene (!) (fats, polyethylene, polypropylene, etc.), and thermoplastic elastomer resins that exhibit rubber elasticity. Foam molded products are not manufactured.This is because when trying to mold thermoplastic elastomer resin in a mold using the bead foaming method, although it foams and fuses, the subsequent shrinkage is large and deformation (shrinkage) occurs. ) is severe, and there are bubbles (
This is because a satisfactory molded product cannot be obtained because the molded product becomes too large. Therefore, foamed molded products with rubber elasticity have conventionally been made by polymerizing while foaming in a mold, like polyurethane foam, but this method has low productivity and the products are made with open cells. Therefore, there was a problem that the compression characteristics were inferior.

An object of the present invention is to enable the production of a highly elastic foam molded article by bead foam molding, which has conventionally been difficult to implement with thermoplastic elastomers, as described above.

The present invention has succeeded in achieving two objectives: the intrinsic viscosity ( ), the density (as measured by density gradient tube method) at 7 degrees; the measuring temperature at 25° C.) or 0. 90 (,)
- ('1, 925 g, 'crn3 1,2-polybutane resin 1).

1.2-Polybutadiene resin is known as a flexible thermoplastic 01 resin that exhibits properties intermediate between those of rubber and plastic resin. Because each structural unit of this resin has a hydrogen atom bonded to a tertiary carbon atom and a vinyl group, it is said that it can be easily crosslinked with sulfur or peroxide in the same way as general rubber H materials. Because of this characteristic, there are many uses51 that take advantage of this characteristic, but it is preferable that the resin constituting the pre-expanded particles of the present invention be non-crosslinked.

1. A method for producing a foam from 2-polybutanoene resin is to add a foaming agent to a 7-len F product of this resin and an ethylene-vinyl acetate copolymer and injection mold it to produce a low-foam molded product! ! A method of manufacturing sponge from a vulcanizate is known, but it is not known to foam only this resin without crosslinking by a bead foaming method to produce a high (II-ratio foamed molded product). 1゜The foamed particles of the present invention have extremely good moldability in in-mold molding, unlike many of the thermoplastic elastomer resin foamed particles, and are suitable for foaming that will be developed in the future. The molded product has excellent flexibility, stiffness and compression recovery.

1. Even with a pre-foamed ladle made of 2-polyphtadiene resin, the density of the resin (1, ri ('l ('l g7'cm)
If the density is less than 0.925 g/cm3, the crystallinity will be low, resulting in poor in-mold molding and shape retention of the V group and molded product, as well as poor heat resistance.If the density exceeds 0.925 g/cm3, the fusion The possible temperature is too high, so the in-mold formability is poor.
. Particularly preferred is a density of 0.905 to 0.920.
g7cm", and the most preferred is a density of 0.
905 to (1,915).

Particularly preferred embodiments of the invention (ii) in relation to the object of the invention
ii The expanded particles have a Q
I: ol, a l ≧ 3. (lcal/gT2-T,
≧ 35°C (QtoLal) cal/δ1 is the total endothermic axillary temperature from the start of melting of the sample to the end of melting, T, r”CI is D S
Heat absorption amount at the maximum heat absorption point of C curve 0) aX) ca
l/g, the lower limit of the temperature range showing the amount of heat absorption of 1/2 or more of CI, T, r'c1 is the -1- limit of the temperature range marked 1-). The pre-expanded particles are made of a 2-polyphtadiene resin which exhibits an endothermic property of 2-polyphtadiene, and exhibit a moldability of γ almost the same as that of cross-linked polyethylene. However, in differential scanning thermal axillary analysis, the sample 1r1mB is
Pour into a capsule and heat from room temperature to about 1.70°C for 2 hours.
This is done by increasing the temperature at a rate of 0''C/min.

The DSC curve is the result of the above differential scan analysis,
It is a curve in which the temperature is set on the +16 axis and 1 endotherm per 1°C is set as the vertical axis. If there are multiple temperature ranges in which the r'18C curve has multiple endothermic peaks and exhibits an amount of endotherm that is half or more of Qmax, 1 is the lower of the lower limits of each temperature range. ), and T2 is taken from the higher -1- limit of each temperature range. Curve I in the drawing
is a DSC curve of a representative example of a pre(1ii+ foam diagonal) according to the present invention.

Conventionally, in the case of polyolefin resins, which have been difficult to perform bead foam molding compared to polystyrene resins, it is common knowledge that the resin can be crosslinked to improve the molding f1°.
The moldability of the expected 1,2-polyphtatsuene resin was not improved at all by crosslinking, and the moldability of the polyolefin was not improved at all by crosslinking. It was surprising that good results were obtained for the first time by giving f;I a constant 1,y endothermic characteristic as shown below.

-) Has bipedal endothermic 1, r properties] Paper polybutanoene fat pre-foamed resin 1.1 has excellent in-all moldability The reason 111 is thought to be as follows. Good Ql, o
Lal is this value], 2-polybutanene cloud 1 is a value proportional to the crystallinity of the fat, as is clear from 2.
Is it possible to make the value 1- or higher than a certain value?], ]2-Polybutadiene tree is just a matter of making the physical properties of polybutadiene trees exhibit to a high degree-1-
is essential. However, if this exposure is too high, molding ■, foaming, etc.!
In addition to being prone to defects, it also has the disadvantage of requiring a large amount of thermal energy for molding. Ql, ol, a
l is preferably in the range of about 3 to 15 (al/6) (particularly desirable values are ='l to I2 (al/
F'+). Also, the value of "l', -T, is 35°C
1? J, j- and my husband, and Su1! In terms of type, showing a DSO curve or a knee endothermic peak like curve 1 in the drawing means that the pre-expanded particle - <= contingency (C) 1 or an algebraic type of particle structure is included. It means needle. ].

] 2-poly/ene (1, r constant crystal with f: part or most of the crystals of fat) -T,
or 35°C i+: 'i The sluggish pre-foamed particles (the 080 curve of a typical example is shown as curve ■ in the drawing) are molded because the temperature range from the actual start of melting to the end of melting is narrow. Sai Foam Book (f M'l!'
When heated to a fine quality, the crystals on both sides tend to melt, and therefore, the bubbles are destroyed until the fusion of particles 1111 and 1111 is completed. Crystal structure and endothermic properties based on it (i.e. melting Q
, 7 properties) of the present invention have a substantial melting point.
Since the temperature range from the start of Qil to the end of melting is wide, if molding is performed at a temperature near the middle of this temperature range, the low melting point crystal part will melt and contribute to the foamed ICIC quantum interlayer, while
High melting point crystal m1 can be prepared without cutting down □1iii
Since the foamed foam particles have a foamed structure of 1, good molding can be carried out.1 Particularly preferred in the 1:1 foamed particles of the present invention is the melting end of the 080 curve-1-. 2 fl' than the temperature
C) Total endotherm on the city side (bordering on temperature but higher than that) 19. 0, + 5 ≦Q11/Qlolal ≦ ()4
5, but is this kind of special thing r?
Ij lft melting point part and quotient? A! l! In the 8° Senbi foamed rib of the present invention, which has just the right and wrong functions in each point part and has particularly excellent moldability, the average cell diameter is approximately 2.
0-2 rl (l f'l horn (preferably 5()~
] 5 f'1 +'l /J), the average number of bubbles is: (
(l +1 pieces/lf1m″j′ (preferably 10(
) pieces/m111″l, u under), the firing j~41゛1-rate is,
E-,50(r'F (bT; mainly to 5, ・10
The average diameter of 1J is within the range of 1-2 + 11111 + 1 (preferably '(-) 5111111), and can be appropriately selected depending on the physical properties of the foamed product to be molded.

According to the present invention] Z-Lin Foamed Nene 1) The particles of 1,2-poly7tadiene resin having a sonic intensity within the above-mentioned range are
Of'1 Junuigawa; use + (l fi-5n t-+
Jujii club water, 3~! '1 ('1 part by weight of a blowing agent (e.g. /chloro/'fluoromethane), (), 1 to 3 parts of a blowing agent (e.g. 'Hui I'/, lJζaluminum oxide)). 1) In a closed container, the measuring strip 1'
The starting material (1') according to 1) is washed once after the melting start temperature of the crystals passing through the SC curve. Impregnated with fat can also be produced by opening the initial outlet hole at the bottom of the container from a pressurized state and releasing the contents into an atmosphere at a lower pressure than the inside of the container. Note that the expanded particles have the preferable thermal properties as described in 111f.
In step 71, the manufacturing process according to method 14 can be carried out in a different temperature state in the above temperature range for 5 to 3 hours. The heating strip fl required to heat dog heat vermilion 5 and 〆1 to l, t-'5 varies depending on the grain size and the degree of crystallinity of taro (raccoon; pestilent).

The pre-expanded particles according to the present invention can be cured in pressurized air when molding a pre-expanded ladle of polystyrene +31 resin or polyolefin 1kj resin in a mold, and when the particles are cured in pressurized air.
KH77cm°(C) Nouchi 1'i':e? It can also be easily molded by filling it with gold 10 and heating it with heat or steam.Especially 1
Those with desirable endothermic properties as described in iir,
Since the range of moldable products is wide, it is easy to mold and large! T
Even when producing a molded article of No. 111, it is possible to easily obtain a perilla product that is homogeneous throughout the entire molded tree. The in-mold molded product produced from the foamed plastic of the present invention has a soft φ retardation, 7-yon properties, and after IT shrinkage, Pl
It has many properties such as 1, r, and is superior to conventional foam molded products.
It is particularly suitable for cushions 4, 4, packaging materials, automatic Ogawa bumper core materials, interior interior materials, etc.

The present invention will be explained below with reference to 1. Examples and Comparative Examples.

Examples and Comparative Examples Average ゛b゛1 diameter 2, ,'' + m + 11 1,2-poly7tanene 1) 1 fatty acid f ``-...1. ('l f)
, t,, water + 2 (1(l g, ti'& Fll-form aluminium oxide, 1.!'i>: tK, J: υ') A blowing agent (column fluoromethane) was placed in a sealed container, and a predetermined amount of l After heating to 1 degree (1 degree) and holding the temperature for 1 hour to impregnate the 431 fat with the foaming agent, the container was heated to a pressure of '! fl Kpr/cm' and the internal pressure was set to '!fl Kpr/cm'. g) The fat particles are foamed by opening the bottom discharge hole and discharging the contents into the atmosphere.

In the method described above, various pre-expanded particles were produced by varying the base oil, the foaming agent, and the added PA/In.

Foam strips 1"l and 11 (iii) foam strips:
The characteristics of f, Tr- are shown in [1].

In addition, by pressurizing and curing with a master (+iii foaming foam F), I, 2 KH,, 11 of 'ctn'' (C)
・t 'j Shitachi: < fl 11111 X 2
+'l (1■nI口X 2 +', l f'l nu
The moldability was tested using a gold rim with an internal diameter of n.

Good moldability! J. Representative molded articles 1 and 1, which were obtained in the test, are shown together with the first person.

The method and molding 1 (evaluation of adhesiveness and v properties) 1) 1 are as follows.

1 molding/bi 1 trial; 1) Method Multiple molding tests were carried out while changing the molding temperature step by step, and the surface of the molded product whose surface direction 1rV44i+・'rI exceeded 7% was uniform and smooth. Molding 711 □ 1 degree is considered to be ``1 [5].For the proper molding temperature, 1 degree from the eye to the lower limit.
The quality of the moldability is determined from the q and y properties of the molded product formed by the width and the moldability 7111X.

沫-1 Nihon 1.71 Office Standard (DNS7.-('l,') li
3) and judged based on the following criteria (however, 1
jl: Tests were omitted for Comparative Examples 3 to 6 in which 11 molded bodies were not obtained.

○: No breakage or cracking at all ×: Compressive elasticity that causes cracking Tested in accordance with JTSK6767 and rated as 1' based on the following criteria (However, 11 cases where a satisfactory molded product was not obtained) Example 3: Tests were omitted for -〇).

O: Compression set 5% or less ×: Compression set exceeds 5%

[Brief explanation of the drawing]

The drawing is a SC curve according to the present invention ((r' of the expanded particle (T) and the contrast field (IT)).

Claims (2)

[Claims] (1) Intrinsic viscosity 0.7 or more, density 11.90 +')
-('l,92,'1 Pre-expanded particles made of crystalline Shinnootakutinoku 1,2-polybutanene LJ resin with H7cm3. (2) 1.2-Polybutadiene resin has its differential scanning heat! In analysis QLol, al ≧ 3. (1cal/RT2-T, ≧
35°C (However, Ql, ol, al [cal/al is the total amount of heat absorbed from the start of melting of the sample to the end of melting, T, ['C1 is D
Endothermic fiQ+nax at the maximum endothermic point of the SC curve (
The lower limit of the quality range, T, r'c], which indicates the amount of heat absorption of 1/2 or more of the total CI, is -1 of the temperature range indicated in -.
The 1,2-polybutadiene pre-expanded particles according to claim 1, which exhibit endothermic properties satisfying the following conditions: