CN111349272A - High-starch-filled HDPE (high-density polyethylene) film blowing master batch and preparation method thereof - Google Patents

Abstract

The invention relates to the field of biodegradable materials, and discloses high-starch-filled HDPE (high-density polyethylene) blown film master batch and a preparation method thereof. The film blowing master batch comprises the following components in percentage by mass: 30-70% of starch, 5-20% of plasticizer, 5-40% of HDPE, 5-20% of flexibilizer, 2-10% of compatilizer, 0.1-1% of lubricant and 0.5-2% of auxiliary agent. The HDPE blown film master batch filled with high starch provided by the invention can be suitable for different blown film equipment after being mixed with different blown film materials, and thin film products with different thicknesses prepared by different equipment can ensure high starch content and have excellent service performance, so that the cost is saved and the environmental protection performance of the product is improved.

Description

High-starch-filled HDPE (high-density polyethylene) film blowing master batch and preparation method thereof

Technical Field

The invention relates to the field of biodegradable materials, in particular to high-starch-filled HDPE (high-density polyethylene) film blowing master batch and a preparation method thereof.

Background

In recent years, the problem of environmental pollution caused by overlong degradation period of disposable plastic products is increasingly serious, degradation materials are more and more valued, and starch filled type degradation materials are more and more adopted due to the cost advantage.

Generally, materials filled with high starch all adopt linear polyethylene (LLDPE) and low-density polyethylene (LDPE) as processing carriers, the addition of starch can cause the reduction of key service performances such as stretching, puncturing and tearing of the materials to different degrees, and the LLDPE and the LDPE have better related performances due to the materials, and the filling with higher starch content can be realized by adjusting the adding proportion.

In the preparation of the film, High Density Polyethylene (HDPE) has higher crystallization degree and high mechanical strength compared with Low Density Polyethylene (LDPE), so that the HDPE is often applied to products with higher strength requirements, such as commodity bags, grocery bags and the like, and shopping bags and takeaway vest bags seen in daily life are all made of HDPE.

However, HDPE has poor tensile toughness and environmental stress cracking due to structural characteristics, and if starch is refilled in the HDPE material, the HDPE loses the usability of the film bag product.

In addition, the conventional HDPE film blowing equipment in the market is different from LDPE film blowing equipment in structure and generally cannot be used universally, the processing temperature of the HDPE material is 20-30 ℃ higher than that of LDPE, the temperature reaches about 175 ℃, and starch is easily decomposed under the processing condition to cause the performance reduction of the material.

Combining the above factors, it has been found that it is almost impossible to find a high starch filled HDPE material suitable for use in HDPE dies on the market.

Disclosure of Invention

The master batch provided by the invention can be blended with different film blowing raw materials, not only can be suitable for LDPE die head processing, but also can be suitable for HDPE die head processing, film products with different thicknesses can be prepared according to the characteristics of two devices, and low-cost starch-based degradable film bag products are prepared, the starch content of the prepared film bag products is more than 30%, the addition amount of starch in a bio-based environment-friendly degradable material or product is further improved, the cost is saved, and the excellent physical properties and the environment-friendly performance of the prepared bio-based environment-friendly degradable film bag product are ensured.

In order to achieve the above object, the present invention provides, in a first aspect, a high starch filled HDPE blowing masterbatch, which comprises the following components in percentage by mass:

30-70% of starch, 5-20% of plasticizer, 5-40% of HDPE, 5-20% of flexibilizer, 2-10% of compatilizer, 0.1-1% of lubricant and 0.5-2% of auxiliary agent.

Preferably, the plasticizer is one or more selected from glycerol, sorbitol and polyethylene glycol 200.

Preferably, the HDPE has a melt index of 20-40g/10 min.

Preferably, the toughening agent is selected from one or more of POE, EAA and EVA.

Preferably, the POE, the EAA and the EVA have the melt index of 20-40g/10 min.

Preferably, the compatibilizer is a grafted combination of MLLDPE, LDPE or POE and maleic anhydride.

Preferably, the grafting rate of the compatilizer MLLDPE-g-MA, LDPE-g-MA or POE-g-MA is more than 0.5%.

Preferably, the lubricant is selected from one or more of PE wax, oxidized PE wax, calcium stearate and zinc stearate.

Preferably, the auxiliary agent is triallyl isocyanate and an antioxidant 1010 according to a mass ratio of 1: 1 is obtained by compounding.

In a second aspect, the present invention provides a method for preparing the masterbatch of the present invention, the method comprising the steps of:

1) adding the starch and the plasticizer into a high-speed mixer, and stirring for 8-10 minutes at the temperature of less than 80 ℃;

2) adding the rest components, stirring for 3-5 min, and discharging;

3) and (3) extruding and granulating by using a parallel double-screw granulator unit to obtain the composite material.

Preferably, the temperature of each section of the double-screw granulator unit is 90-175 ℃, and the screw rotating speed is 300-400 rpm.

Compared with the prior art, the invention has the following beneficial effects:

1. the optimized components and the proportion of the high-starch-filled HDPE blown film master batch provided by the invention can ensure that the addition amount of starch in a film bag product reaches more than 30%, and has a great cost advantage;

2. aiming at different processing equipment provided with different die heads such as HDPE, LDPE and the like, stable production can be realized by mixing different film blowing raw materials;

3. the starch-based film bag product prepared from the high-filling HDPE blown film master batch provided by the invention has excellent performance; the bag is suitable for various packaging bags and/or sealing bags, in particular to express bags, hand bags, vest bags, rope-penetrating bags, flat bags, button bags, zipper bags, edge sealing bags, hand bags, rope drawing bags and the like.

Additional features and advantages of the invention will be set forth in the detailed description which follows.

Detailed Description

The following describes in detail specific embodiments of the present invention. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

The present invention will be described in detail below by way of examples. In the following examples, each material used was commercially available unless otherwise specified, and the method used was a conventional method in the art unless otherwise specified.

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

In a first aspect, the invention provides a high starch filled HDPE blown film masterbatch, which comprises the following components in percentage by mass:

30-70% of starch, 5-20% of plasticizer, 5-40% of HDPE, 5-20% of flexibilizer, 2-10% of compatilizer, 0.1-1% of lubricant and 0.5-2% of auxiliary agent.

The addition amount of the masterbatch starch in the bio-based environment-friendly degradable film bag product is adjusted through the optimized components and the proportion of the HDPE blown film masterbatch filled with high starch, so that the product performance, the production cost and the environment-friendly performance can be adjusted according to the use requirements.

In the present invention, preferably, the blown film masterbatch comprises the following components by mass:

40-60% of starch, 6-14% of plasticizer, 10-35% of HDPE, 5-15% of flexibilizer, 3-8% of compatilizer, 0.1-1% of lubricant and 0.5-2% of auxiliary agent.

The starch is not particularly limited, and various industrial or food grade starches available on the market, including but not limited to corn starch, potato starch, tapioca starch, wheat starch, sorghum starch and mixed bean starch, can be determined by those skilled in the art according to the actual use requirements. In the present invention, preferably, the starch is selected from one or more of corn starch, potato starch, tapioca starch, wheat starch and sorghum starch.

The plasticizer is not particularly limited, and may be various plasticizers commonly used in the art, such as alcohols, esters, vegetable acids, and the like, and in the present invention, in order to increase the amount of starch to be added in subsequent products and ensure excellent performance of the products, it is preferable that the plasticizer is selected from one or more of glycerin, sorbitol, and polyethylene glycol 200.

The HDPE is not limited by manufacturers and brands, but in order to ensure the processing fluidity of the final blown film master batch, the melt index of the HDPE is preferably 20-40g/10 min.

In order to ensure the tensile toughness and the environmental stress cracking resistance of the subsequent product in use, in the invention, preferably, the toughening agent is selected from one or more of POE, EAA and EVA; more preferably, the POE, EAA and EVA have a melt index of 20-40g/10 min.

In order to reduce the particle size of starch and improve the dispersion performance of starch in the blown film masterbatch and subsequent products, in the invention, the compatibilizer is preferably a grafted combination of MLLDPE, LDPE or POE and maleic anhydride; more preferably, the grafting ratio of the compatibilizer MLLDPE-g-MA, LDPE-g-MA or POE-g-MA is 0.5% or more.

In order to improve the processing performance of the blown film master batch during granulation and blown film, preferably, the lubricant is selected from one or more of PE wax, oxidized PE wax, calcium stearate and zinc stearate.

In order to improve the thermal stability of the material processing process and the aging resistance of the subsequent product for continuous use, the auxiliary agents are preferably triallyl isocyanate and an antioxidant 1010; more preferably, the auxiliary agent is triallyl isocyanate and an antioxidant 1010 according to a mass ratio of 1: 1 is obtained by compounding.

In a second aspect, the invention provides a preparation method of the master batch, which comprises the following steps:

1) adding the starch and the plasticizer into a high-speed mixer, and stirring for 8-10 minutes at the temperature of less than 80 ℃;

2) adding the rest components, stirring for 3-5 min, and discharging;

3) and (3) extruding and granulating by using a parallel double-screw granulator unit to obtain the composite material.

In the method of the invention, the temperature of each section of the twin-screw granulator unit is preferably 90-175 ℃, and the screw rotation speed is 300-400 rpm.

The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples.

All the starting materials used in the examples are commercially available, except where otherwise indicated.

The performance test method comprises the following steps:

tensile strength, tearing strength, pendulum impact resistance and puncture strength test: and testing according to a corresponding national standard testing method.

And (3) testing tensile property: according to the test of GB/T1040.3-2006, the sample adopts type 2, the length is 150mm, the width is 15mm, and the test speed is 200 mm/min. Detecting data of the sample in the longitudinal direction and the transverse direction;

and (3) testing the tearing strength: the method is carried out according to the regulation of GB/T16578.2-2009. Detecting data of the sample in the longitudinal direction and the transverse direction;

pendulum impact resistance: testing according to GB/T8809-2015 standard;

puncture strength: testing according to GB/T10004-2008 standard;

the unit of tensile strength is N, the unit of tensile strength is MPa, the unit of elongation at break is%, the unit of pendulum impact resistance is J, and the unit of puncture strength is N.

Example 1

43% of corn starch, 9% of sorbitol, 25% of HDPE, 15% of EAA, 7% of MLLDPE-g-MA, 0.5% of PE wax, 0.25% of triallyl isocyanate and 10100.25% of antioxidant.

Example 2

50% of corn starch, 10% of glycerol, 25% of HDPE, 9% of EVA, 5% of LDPE-g-MA, 0.5% of oxidized PE wax, 0.25% of triallyl isocyanate and 10100.25% of antioxidant.

Example 3

60% of corn starch, 20014% of polyethylene glycol, 15% of HDPE, 5% of POE-g-MA, 0.25% of PE wax, 0.25% of zinc stearate, 0.25% of triallyl isocyanate and 10100.25% of antioxidant.

Starch and plasticizer were added to a high speed mixer in the proportions shown in examples 1-3 and stirred at 500rpm for 10 minutes at 80 ℃; then adding the carrier, the compatilizer, the lubricant and the auxiliary agent according to the proportion, continuously stirring for 5 minutes at normal temperature, and discharging for later use;

extruding and granulating by using a parallel double-screw granulator set, and setting the temperature of each area of the double-screw extruder as follows: first region 90 deg.C, second region 140 deg.C, third region 145 deg.C, fourth region 150 deg.C, fifth region 155 deg.C, sixth region 155 deg.C, seventh region 155 deg.C, eighth region 155 deg.C, ninth region 155 deg.C, tenth region 155 deg.C, eleventh region 155 deg.C, twelfth region 155 deg.C, thirteenth region 160 deg.C, and head 160 deg.C; setting the rotation speed of the screw at 380rpm to obtain starch master batches M1-M3.

Preparation of film products L1-L4

Mixing the prepared starch master batches M1-M3 and PE according to the following proportions:

TABLE 1

Film product	Master batch	LLDPE	LDPE
				L1	70％M1	15％	15％
L2	60％M2	20％	20％
				L3	50％M3	25％	25％
L4	60％M3	30％	10％

Films were prepared using a conventional 55-type inflation film machine, 200mm diameter LDPE die:

after mixing the raw materials, putting the raw materials into a film blowing machine for film blowing, and setting the temperature of each area of the film blowing machine as follows: the film product L1-L3 with the thickness of 0.06mm is obtained by the steps of first zone 160 ℃, second zone 165 ℃, third zone 170 ℃, fourth zone 170 ℃, fifth zone 170 ℃, upper die head 170 ℃ and lower die head 170 ℃.

Preparation of film product H1-H4

Mixing the prepared starch master batches M1-M3 and PE according to the following proportions:

TABLE 2

Film product	Master batch	LLDPE	HDPE
				H1	70％M1	10％	20％
H2	60％M2	10％	30％
				H3	50％M3	10％	40％
H4	60％M3	10％	30％

Using a conventional 55 type film blowing machine, a 60mm diameter HDPE die head to prepare a film:

after mixing the raw materials, putting the raw materials into a film blowing machine for film blowing, and setting the temperature of each area of the film blowing machine as follows: the first zone is 165 ℃, the second zone is 170 ℃, the third zone is 175 ℃, the fourth zone is 175 ℃, the fifth zone is 175 ℃, the upper die head is 175 ℃ and the lower die head is 175 ℃ to obtain the film products H1-H3 with the thickness of 0.025 mm.

Test example

L1-L4 and H1-H4 were tested and the results are shown in Table 3 below.

TABLE 3

As can be seen from table 3, the HDPE blown film masterbatch filled with high starch provided by the invention can satisfy different blown film equipment by mixing different blown film raw materials, when the required film thickness is large, L-series films can be prepared, and when the required film thickness is small, H-series films can be prepared, and the prepared film products have excellent uniformity and meet the use requirements, and the starch content of the products can reach more than 30%.

The materials used in the above examples are conventional products available on the market, the starch used is edible corn starch (premium product), the plasticizer adopts a raw material of biological source, the melt index of the HDPE carrier used for granulation is 20g/10min, the melt indexes of the toughening agents EAA, EVA and POE are 20g/10min, the grafting ratio of the MLLDPE-g-MA used is 0.6%, the grafting ratio of the LDPE-g-MA is 1.0%, and the grafting ratio of the POE-g-MA is 1.2%, the lubricant used is purchased from Shanghai Hua sparkling chemical auxiliary agent Limited, and the auxiliary agent used is also a conventional product on the market. In the used PE blown film material, the melt index of LDPE is 2g/10min, the melt index of LLDPE is 2g/10min and the melt index of HDPE is 0.04g/10 min.

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.

Claims (10)

1. The high-starch-filled HDPE (high-density polyethylene) blown film master batch is characterized by comprising the following components in percentage by mass:

30-70% of starch, 5-20% of plasticizer, 5-40% of HDPE, 5-20% of flexibilizer, 2-10% of compatilizer, 0.1-1% of lubricant and 0.5-2% of auxiliary agent.

2. The high starch filled HDPE blown film masterbatch of claim 1 wherein said plasticizer is selected from one or more of glycerol, sorbitol and polyethylene glycol 200.

3. The high starch filled HDPE blown film masterbatch of claim 1 wherein the HDPE has a melt index of 20-40g/10 min.

4. The high starch filled HDPE blown film masterbatch of claim 1 wherein the toughening agent is selected from one or more of POE, EAA and EVA;

preferably, the POE, the EAA and the EVA have the melt index of 20-40g/10 min.

5. The high starch filled HDPE blown film masterbatch of claim 1 wherein said compatibilizer is a grafted combination of MLLDPE, LDPE or POE with maleic anhydride.

6. The high starch filled HDPE blown film masterbatch of claim 5, wherein the compatibilizer MLLDPE-g-MA, LDPE-g-MA or POE-g-MA has a grafting ratio of 0.5% or more.

7. The high starch filled HDPE blown film masterbatch of claim 1 wherein said lubricant is selected from one or more of PE wax, oxidized PE wax, calcium stearate and zinc stearate.

8. The high starch filled HDPE blown film masterbatch of claim 1, wherein the auxiliary agent is triallyl isocyanate and antioxidant 1010 in a mass ratio of 1: 1 is obtained by compounding.

9. A process for the preparation of a masterbatch according to any one of claims 1 to 8, characterized in that it comprises the following steps:

1) adding the starch and the plasticizer into a high-speed mixer, and stirring for 8-10 minutes at the temperature of 80 ℃;

2) adding the rest components, stirring for 3-5 min, and discharging;

3) and (3) extruding and granulating by using a parallel double-screw granulator unit to obtain the composite material.

10. The preparation method according to claim 9, wherein the temperature of each section of the twin-screw granulator unit is 90-175 ℃, and the screw rotation speed is 300-400 rpm.