JPS59157136A - Polyolefin resin sheet - Google Patents

Abstract

PURPOSE:The titled sheet having high strength and rigidity and appearance like paper, especially improved heat molding properties, and low drawdown, obtained by blending a specific polypropylene resin with a spcified polyethylene resin and talc in a molten state. CONSTITUTION:(A) A polypropylene resin having 0.1-5.0g/10min melt index is blended with (B) a polyethylene resin (e.g., high-density polyethylene having 0.940-0.970g/cm<3> specific gravity) having 0.02-10.0g/10min melt index and (C) talc (preferably 10-20mu particle diameter) in a molten state, to give the desired sheet (preferably for heat molding). A total amount of the component A and B is 40-80wt% based on total amount of blend, and an amount of the component A is preferably 10-90wt% based on total amount of the components A and B. USE:Synthetic thick paper, containers for foods and drinks, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyolefin resin sheet, and more specifically, a polyolefin resin sheet that has high strength, high rigidity, and has a paper-like appearance, has particularly excellent thermoformability, and is suitable for various uses. The present invention relates to a resin sheet. □ ゛゛It is well known that blending inorganic fillers with conventional polypropylene resins improves the heat resistance, rigidity, incineration properties, etc. of Baboliglobilene resins. ・These polypropylene resins and pyrene resins Taking advantage of its characteristics, the composition is molded into various molded products by injection molding, extrusion molding, etc. Among these, polyglopylene resin sheets are mainly used for manufacturing molded products such as various containers, cups, and trays by secondary molding, that is, vacuum forming or pressure forming. However, polypropylene resin has sharp melting characteristics compared to other resins, so the strength of the melt is low, and the drawdown due to heating during preheating when molding is secondary in thermoforming is large. There were drawbacks that appeared in the molded product, such as wrinkles and uneven thickness. Furthermore, when a relatively large amount of inorganic photonic agent is added to improve rigidity and incineration properties, thermoformability decreases, making it difficult to mold deep products, and the mechanical strength is insufficient. I couldn't get it. Therefore, it is extremely difficult to use it for cups, etc., and it has not yet been put to practical use.

For this reason, various proposals have been made to make the surface of the inorganic filler lipophilic, or to incorporate higher fatty acids or their gold salts, etc., in order to improve the mechanical strength and surface properties of the sheet. However, the lipophilic treatment requires a treatment step, and the treatment agent bleeds onto the surface or is eluted, which poses safety problems when used as containers for foods and beverages.

Furthermore, although the sheets formed by these methods have good surface properties, their thermoformability is rather poor and they also have an odor, so their field of application has been greatly restricted.

Another method of adding rubber has been proposed, but it is unfavorable in terms of heat resistance, rigidity, and odor, and when used in foods containing fat, the rubber components will dissolve and cause a bad odor. It has major drawbacks such as becoming (-).

The present inventors conducted intensive research to overcome the essential drawbacks of conventional polypropylene resin sheets, such as drawdown during thermoforming, thermoformability, and physical properties. The present inventors have discovered that sheets obtained from compositions in which talc is blended with a resin compound can be improved without causing food hygiene problems, and have completed the present invention.

That is, the present invention fl, (A) melt index a1~
Melt-molding a compound consisting of a polypropylene resin of 5.0y-710 minutes, (B) a polyethylene resin with a melt index One sheet is provided.

The polypropylene resin in the present invention is not particularly limited, but includes homopolymers of propylene, block copolymers of propylene and other α-olefins such as ethylene having a weight ratio of 20 or less, and mixtures thereof. Also, the melt index is 01~5.0f/-/1
- 0 minutes, preferably α2-3.0fil-710 minutes, more preferably cL6-t5V10 minutes. If the melt index exceeds 51i'/10 minutes, the forced melting of the sheet will be small, and if it is less than αI P/10 minutes, the fluidity will be poor, making secondary formability such as thermoforming difficult. . The polypropylene resin can be selected as appropriate depending on the purpose of use of the sheet. For example, glopylene homopolymer is used for retort-related products that require heat resistance and rigidity, and for frozen foods that require cold resistance and impact resistance. A relationship such as a globylene-ethylene block copolymer is selected.

Next, the polyethylene resin I5 in the present invention is not particularly limited, and includes high-density polyethylene, medium-density polyethylene, and low-density polyethylene. Random or block copolymers are available. Here, the density of madder density polyethylene is 1-1, and the density is α940 to α970 f/CfA.
belongs to. Medium- and low-density polyethylenes include high-pressure polyethylene and copolymers of ethylene obtained by medium- and low-pressure processes with α-olefins having 3 to 12 carbon atoms, such as propylene, butene-1,4-methylpentene-1, and octene-1. There is a so-called linear low-density polyethylene.

I Here, the α-olefin content U is preferably in the range of 15 to 30. The density of these medium/low density polyethylenes is usually α900 to α940 p/cd. In addition, the melt index of polyethylene resin is [1
02~1 [10ff/10 minutes, preferably α06~5
．． 0y-710 minutes, more preferably 11:(104-2, O
p/10 minutes. If the melt index is outside these ranges, it will not be good (2) in terms of melt-kneaded sheet formability and secondary formability such as thermoforming.

Each of these polyethylene resins can be used alone (-1) or two or more types can be used in a mixture (1-).The selection of polyethylene resins is based on the melt index range mentioned above, and a comparison of melt strength. It is desirable to use a resin with a high molecular weight distribution, that is, a resin with a wide molecular weight distribution, or a method of blending two or more types so as to widen the molecular weight distribution.

In the present invention, the polyolefin resin and 1- (A
) Melt index (11 to 5.05'/10 minutes of polypropylene resin and (B) Melt index [L0
2~1αOF! It is necessary to use both the polyethylene resin of -/10 min, and the blending ratio thereof is not particularly limited and may be determined according to various conditions.

However, in general, the total amount of both resins (A) and (B) is
~ (N polypropylene resin 10 to 90% by weight, (B
) Polyethylene resin is selected within the range of 90 to 10 weight ratio. When the blending amount of the polypropylene resin increases, the elongation during thermoforming improves, making it easier to obtain deep products such as cups, but the drawdown is large and the aging formability is poor.

On the other hand, if the amount of polyethylene resin (B) is too large, the elongation will be small and deep molding will be difficult, whereas if the amount is too small, the drawdown phenomenon will be large and thermoformability will be poor. Therefore, it is best to determine the optimum blending ratio depending on the resin properties of each resin (A) and (B), the blending of talc, which will be discussed later, the use of the sheet, etc. For example, as a thermoformable sheet for deep molding, globylene homopolymer
4D to 90 MIWk% and high density polyethylene with a wide molecular weight distribution in the range of 60 to 10% by weight 1. You can use whatever you have.

two The next component, talc, is its shape.

There are no particular restrictions on particle size, etc., but the average particle size is 10~
20μ is preferable (-).Here, talc is hydrated magnesium silicate, for example, 5i0250 to 65%
, Mg025-40% and other components, and has a loss on ignition of 4-6%.

The formulation in the present invention includes the aforementioned (Δ), (B),
It consists of component (C), and its blending ratio is not particularly limited, but usually the total amount of (A) polypropylene resin and (R) polyethylene resin is 4Q based on 1-4Q of the entire blend.
to 80, heavy J, t% and j-2 (C) talc to 60~2
Preferably, the total iTI of both resins (A) and (B) is 45 to 75% by weight, and (C) talc is in the range of 55 to 25% by weight. If the amount of talcry added increases, the rigidity and incineration properties will improve, but the melt-kneaded sheet formability and secondary formability such as thermoforming will decrease, so it must be determined appropriately in consideration of the use of the sheet.

Furthermore, various types of talc can be used; for example, for sheets used in food-related fields, highly purified talc or acid-treated talc to remove impurities is used. You can also do that. In the present invention, by selecting talc from among the inorganic photonic agents mentioned above, we have succeeded in obtaining a product that is completely free from food hygiene problems.

In the present invention, the surface treatment of talc Jl! I! Although this is not particularly necessary, the talc surface may be subjected to lipophilic treatment 1',' in order to improve mechanical properties. This is a specific example of these treatments and 1 to 1.
There are products in which an activator, a polymerizable monomer, an oligomer, and a silane coupling agent that form a lipophilic group (2. A polyolefin resin modified with an unsaturated carboxylic acid or a derivative thereof, such as maleic anhydride, may be added in a range of from 1 to 2%.Furthermore, antioxidants, ultraviolet absorbers, antistatic agents, Pigments and the like can also be added.

The polyolef, in-based resin sheet of the present invention has the above-mentioned (4)
, o3), and (C) are sufficiently kneaded using a conventional kneading method, i.e., a roll, a ball mixer, a single-screw extruder, a multi-screw extruder, extrusion, etc. It can be obtained by sheet-forming using a die method or an I-die method. The thickness of the sheet is usually 0.3-C1 depending on the use of the obtained sheet. '2Z,, Huni9464□, *aU'AQ :) A
: V,74 resin sheet has 6) high strength, rigidity,
Heat resistance, non-glossy white paper-like appearance, no odor, high safety with no filler elution, zero calorific value of 5500
~65[ ] It has the characteristics of low incineration properties such as low cat/1, no melting and solidification, no damage to the furnace wall, etc. These characteristics can be utilized for various purposes such as synthetic cardboard, etc. Can be used for cardboard, carton boxes, etc.

Another major feature of the sheet of the present invention is that it has little drawdown and elongation in secondary thermoforming such as vacuum forming or pressure forming, making it possible to form deep objects without wrinkles or uneven thickness. It's what I did. This, combined with features such as food hygiene, water resistance, hot water resistance, and oil and fat resistance, as well as printability, thinner walls, and high productivity through high-speed continuous production, makes it ideal for containers for various foods and beverages.
This makes it possible to greatly expand its field of use.

The present invention will be further explained below with reference to Examples, but the present invention is not limited thereto.

Examples 1 to 12 and Comparative Examples 1 to 3 Predetermined amounts of polypropylene, polyethylene,
After kneading talc using a Banbury mixer and pelletizing it, using an extruder it was made into pellets with a width of 500 mm and a thickness of 0.8 mm.
Got a sheet of duck. Tensile strength and elongation of the obtained sheet: 9
The measurement results of the elastic modulus are shown in Table 1. In addition, the obtained sheet was clamped in a frame of 300 meters x 300 meters and heated with an upper heater. Table 1 shows the measurement results of the drawdown after 85 seconds and the evaluation results of the moldability when the beverage cup was molded. (Cup diameter 7o
Thin, height 9071111) *1 Dense W (191f/
cl, melt index [16P/10 minutes *2 density 2 α90 f/C1/! , melt index
toy/io bulk chestnut 3 density 0.964P/Cl/1.
) Luto index Q, 4 P/10 minutes *4 minute density 4 α9557/71! , melt index
α05P/10min*5 Density 0.919P/m, Melt index tar/1omin*6 Density α92
4 f/(go, melt index [L55P/10
Min*7 Density α922P/7. Melt index α7? /10 minutes *8. *9. *10 JIS K
Patent applicant pursuant to 6734: Idemitsu Petrochemical Co., Ltd. Calg Industries Co., Ltd.

Claims (1)

[Claims] (1) (A) Melt index 11 to '5.01?
/10 minutes polypropylene resin, (B) melt index [102 to 1 [LOP/1] polyolefin resin sheet made by melt-molding a blend consisting of polyethylene resin and (Q talc). (2) The total amount of (4) voribropyran resin and (B) polyethylene resin in the formulation is
The resin sheet according to claim 1, which has a weight I of 1%. (3) The polypropylene resin in the compound is (A). (B) The resin sheet according to claim 1, wherein the total amount of both resins is 10 to 90% by weight.・(4) (
A) The resin sheet according to claim 1, wherein the polypropylene resin is a propylene homopolymer or a block copolymer with other α-olefins. (5) The resin sheet according to claim 1, wherein the sheet is in a matured shape.