CN111331800A - Injection molding process capable of preventing injection overflow - Google Patents

Injection molding process capable of preventing injection overflow Download PDF

Info

Publication number
CN111331800A
CN111331800A CN202010142386.5A CN202010142386A CN111331800A CN 111331800 A CN111331800 A CN 111331800A CN 202010142386 A CN202010142386 A CN 202010142386A CN 111331800 A CN111331800 A CN 111331800A
Authority
CN
China
Prior art keywords
injection molding
injection
density polyethylene
molding process
granules
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN202010142386.5A
Other languages
Chinese (zh)
Other versions
CN111331800B (en
Inventor
余爱国
汪海龙
程俊义
姚宏奎
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Novel Huangshan Packaging Co Ltd
Original Assignee
Novel Huangshan Packaging Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Novel Huangshan Packaging Co Ltd filed Critical Novel Huangshan Packaging Co Ltd
Priority to CN202010142386.5A priority Critical patent/CN111331800B/en
Publication of CN111331800A publication Critical patent/CN111331800A/en
Application granted granted Critical
Publication of CN111331800B publication Critical patent/CN111331800B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/0001—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor characterised by the choice of material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/17—Component parts, details or accessories; Auxiliary operations
    • B29C45/76—Measuring, controlling or regulating
    • B29C45/78—Measuring, controlling or regulating of temperature
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
    • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
    • C08L23/04—Homopolymers or copolymers of ethene
    • C08L23/06—Polyethene
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2023/00—Use of polyalkenes or derivatives thereof as moulding material
    • B29K2023/04—Polymers of ethylene
    • B29K2023/06—PE, i.e. polyethylene
    • B29K2023/0608—PE, i.e. polyethylene characterised by its density
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2205/00—Polymer mixtures characterised by other features
    • C08L2205/02—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group
    • C08L2205/025—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2207/00—Properties characterising the ingredient of the composition
    • C08L2207/06—Properties of polyethylene
    • C08L2207/062—HDPE
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2207/00—Properties characterising the ingredient of the composition
    • C08L2207/06—Properties of polyethylene
    • C08L2207/066—LDPE (radical process)

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Injection Moulding Of Plastics Or The Like (AREA)

Abstract

The invention relates to an injection molding process for preventing injection overflow, which relates to the field of injection molding processes, and is used for preparing modified polyethylene: mixing low-density polyethylene, high-density polyethylene and a slipping agent according to the weight part ratio, and uniformly stirring to obtain blend granules; injection molding: adding the blend granules into a hopper of an injection molding machine, melting the blend granules in a heating cylinder through a heating screw to form fluid with uniform properties, and performing injection, pressure maintaining, cooling forming and demolding by adopting a sprue mold to obtain the product. The invention overcomes the extension phenomenon of the melted granules by discussing different melting value attributes of the granules and using the speed and the quantity of effective regulating and melting, and solves the problem that the product has concentric circle residues on the appearance.

Description

Injection molding process capable of preventing injection overflow
Technical Field
The invention relates to the field of injection molding processes, in particular to an injection molding process capable of preventing injection overflow.
Background
Injection molding production control is used to put single granules into use to simplify production process control and pursue stability and uniqueness of quality of produced products. However, the product produced by using a single pellet cannot satisfy the market demand and the molding appearance requirement due to the application requirements of the product and the constraints of the application environment.
Taking the production of a hot runner needle valve type gate inlet product as an example: in the injection molding production, under the action of the air pressure controlled by an electronic valve, the needle valve thimble can repeatedly perform telescopic motion on a mold cavity, or melt overflows due to the fact that a movement gap of the thimble overflows or a gap exists due to abrasion of the mold cavity. The excessive material is a microcosmic concept, and more expression modes are granule molecules carried in hot air, and because of the cooling effect in the repeated injection molding production process, the granule molecules can be reduced into solid powder, and the granule molecules are attached to the position near a mold inlet gate, and the trace solid powder granules near the inlet gate can be transferred to the corresponding position of a product in the continuous production process, so that the appearance of the product is influenced, even waste products are produced, and the phenomenon that irregular concentric circle residues A are formed at the position of the inlet gate B of the product is mainly expressed.
Moreover, the existing process controls the production material to be single, keeps the original attribute of single granules after melt injection molding, and cannot effectively adjust the melting speed and quantity under stable process conditions, i.e. cannot complete switching within unit time and has the extension of the original attribute, like the inertia extension after braking, so that the injection molding process for preventing injection overflow needs to be provided to solve the problems.
Disclosure of Invention
In order to solve the technical problems, the invention aims to provide an injection molding process for preventing injection overflow.
In order to realize the purpose of the invention, the invention adopts the following technical scheme: an injection molding process for preventing injection overflow comprises the following steps:
(1) preparing modified polyethylene: mixing 900-990 parts of low-density polyethylene, 9-99 parts of high-density polyethylene and 1 part of slipping agent according to the weight part ratio, and uniformly stirring to obtain blend granules;
(2) injection molding: adding the blend granules obtained in the step (1) into a hopper of an injection molding machine, melting the blend granules in a heating cylinder through a heating screw to form fluid with uniform properties, and performing injection, pressure maintaining, cooling forming and demolding by adopting a sprue mold to obtain the product.
Preferably, the mass ratio of the low-density polyethylene to the high-density polyethylene to the slipping agent is 970: 29: 1.
Preferably, the slip agent component is erucamide.
Preferably, the low-density polyethylene is of the trade name M050X in Malaysia, the high-density polyethylene is of the trade name Dushan DMDA8008, and the slip agent is of the trade name SLPP-7 in Beijing Asian.
Preferably, the temperature of a charging barrel of the injection molding machine is 190-200 ℃, the temperature of a nozzle is 190-200 ℃, the temperature of a mold is 30-35 ℃, and the pressure maintaining time is 0.5-1.0 min.
The invention has the beneficial effects that:
(1) malaysia M050X in the ingredients of the invention belongs to LDPE, namely low density polyethylene, and has the characteristic of high fluidity, and if only low density polyethylene is used in the application of injection molding, the phenomenon of hot runner point sprue overflow is easy to occur; and the temperature in the mold cavity is lower than the temperature of the runner, and the overflowing colloid is rapidly cooled to form cold materials, so that the quality of the subsequent injection molding product is adversely affected. The Dushan DMDA8008 adopted in the invention belongs to HDPE, namely high density polyethylene, is a non-polar thermoplastic resin with high crystallinity, and is nontoxic, tasteless and odorless white particles; since it is the proper combination of four basic variables that determine the properties of HDPE: density, molecular weight distribution and additives, where density is the main variable determining the properties of HDPE, higher molecular weight results in higher polymer viscosity, which is manifested by poor flow on injection molding. Therefore, the two particles are mixed according to a certain proportion, and then melted by the heating screw to form fluid with uniform properties, so that the fluidity of the fluid can be better controlled, the probability of overflow phenomenon of the raw material taking LDPE as a main body in the application of a mold is reduced, and the quality problem caused by overflow cold material, such as concentric circular residues on the periphery of a pouring gate possibly generated in production, is effectively avoided.
The slipping agent in the ingredients is erucamide slipping agent, which can obviously reduce the dynamic and static friction coefficients of the surface of the product and effectively improve the easy processability and the packaging operation efficiency of the plastic; the coating has excellent antistatic performance, and can effectively prevent the deposition of microparticles on the surface of a product, thereby reducing the generation of fog rings; the flowability of the melt colloid is regulated by M050X and DMDA8008 in the ingredients, and the convenience and the speed of demoulding of the Beijing Asian SLPP-7 regulator product in the ingredients are improved, so that the appearance of the product possibly generated in production is improved and the product has concentric residues.
(2) According to the invention, three kinds of granules with different attributes are fused together through the common melting cavity, the density of the formed melt and the flow rate after stress action are adjusted, the stable performance of the melt in the forming cavity is ensured, no residue is generated when the melt repeatedly flows through the needle valve, the overflow problem of the product after the granules are melted and injected is effectively solved, the appearance of the product is improved and stabilized, and the production continuity is ensured.
Drawings
FIG. 1 is a schematic flow diagram of the present invention;
FIG. 2 is a schematic view showing the surface shape of a transparent inferior product of the present invention;
FIG. 3 is a schematic view of the surface shape of the transparent genuine article according to the present invention;
Detailed Description
The technical solution of the present invention is further described in detail below with reference to the accompanying drawings and the detailed description.
Example 1
The injection molding process for preventing injection overflow comprises the following steps:
(1) preparing modified polyethylene: mixing 900 parts of low-density polyethylene, 99 parts of high-density polyethylene and 1 part of slipping agent, and stirring for 10 minutes to obtain uniform blend granules;
(2) injection molding: adding the blend granules obtained in the step (1) into a hopper of an injection molding machine, melting the blend granules in a heating cylinder through a heating screw to form fluid with uniform properties, and performing injection, pressure maintaining, cooling forming and demolding by adopting a sprue mold to obtain the product.
Example 2
The injection molding process for preventing injection overflow comprises the following steps:
(1) preparing modified polyethylene: mixing 950 parts of low-density polyethylene, 49 parts of high-density polyethylene and 1 part of slipping agent, and stirring for 10 minutes to obtain uniform blend granules;
(2) injection molding: adding the blend granules obtained in the step (1) into a hopper of an injection molding machine, melting the blend granules in a heating cylinder through a heating screw to form fluid with uniform properties, and performing injection, pressure maintaining, cooling forming and demolding by adopting a sprue mold to obtain the product.
Example 3
The injection molding process for preventing injection overflow comprises the following steps:
(1) preparing modified polyethylene: mixing 970 parts of low-density polyethylene, 29 parts of high-density polyethylene and 1 part of slipping agent, and stirring for 10 minutes to obtain uniform blend granules;
(2) injection molding: adding the blend granules obtained in the step (1) into a hopper of an injection molding machine, melting the blend granules in a heating cylinder through a heating screw to form fluid with uniform properties, and performing injection, pressure maintaining, cooling forming and demolding by adopting a sprue mold to obtain the product.
Example 4
The injection molding process for preventing injection overflow comprises the following steps:
(1) preparing modified polyethylene: mixing 990 parts of low-density polyethylene, 9 parts of high-density polyethylene and 1 part of slipping agent, and stirring for 10 minutes to obtain uniform blend granules;
(2) injection molding: adding the blend granules obtained in the step (1) into a hopper of an injection molding machine, melting the blend granules in a heating cylinder through a heating screw to form fluid with uniform properties, and performing injection, pressure maintaining, cooling forming and demolding by adopting a sprue mold to obtain the product.
Comparative example
The traditional injection molding process comprises the following steps:
preparing modified polyethylene: mixing 999 parts of low-density polyethylene and 1 part of slipping agent, and stirring for 10 minutes to obtain uniform blend granules;
(2) injection molding: adding the blend granules obtained in the step (1) into a hopper of an injection molding machine, melting the blend granules in a heating cylinder through a heating screw to form fluid with uniform properties, and performing injection, pressure maintaining, cooling forming and demolding by adopting a sprue mold to obtain the product.
Table 1:
Figure BDA0002399533830000051
FIG. 2 shows the surface shape of a transparent defective product, wherein a small dot is an inlet gate, and a shadow is a defective phenomenon caused by flash; FIG. 3 shows the surface shape of a transparent genuine product, and the small dots are inlet gates. As can be seen from Table 1, the data obtained for examples 1-4 are all superior to the data for the comparative example, indicating that the material produced by the process of the present invention exhibits fewer defects than the prior art, and the product produced by example 3, which has the smallest concentric circle residual area, is the best injection molding process to prevent injection flash, and therefore the injection molding process of the present invention represents a significant improvement.
The above embodiments are only for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may be modified or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims (5)

1. An injection molding process for preventing injection overflow is characterized by comprising the following steps:
(1) preparing modified polyethylene: mixing 900-990 parts of low-density polyethylene, 9-99 parts of high-density polyethylene and 1 part of slipping agent according to the weight part ratio, and uniformly stirring to obtain blend granules;
(2) injection molding: adding the blend granules obtained in the step (1) into a hopper of an injection molding machine, melting the blend granules in a heating cylinder through a heating screw to form fluid, and performing injection, pressure maintaining, cooling forming and demolding by adopting a sprue mold to obtain the product.
2. An injection molding process for preventing injection flooding as claimed in claim 1, wherein: the mass ratio of the low-density polyethylene to the high-density polyethylene to the slipping agent is 970: 29: 1.
3. An injection molding process for preventing injection flooding as claimed in claim 1, wherein: the slipping agent comprises erucamide.
4. An injection molding process for preventing injection flooding as claimed in claim 1, wherein: the grade of the low-density polyethylene is M050X in Malaysia, the grade of the high-density polyethylene is Dushan DMDA8008, and the grade of the slipping agent is SLPP-7 in Beijing Asian.
5. An injection molding process for preventing injection flooding as claimed in claim 1, wherein: the temperature of a charging barrel of the injection molding machine is 190-200 ℃, the temperature of a nozzle is 190-200 ℃, the temperature of a mold is 30-35 ℃, and the pressure maintaining time is 0.5-1.0 min.
CN202010142386.5A 2020-03-04 2020-03-04 Injection molding process capable of preventing injection overflow Active CN111331800B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010142386.5A CN111331800B (en) 2020-03-04 2020-03-04 Injection molding process capable of preventing injection overflow

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010142386.5A CN111331800B (en) 2020-03-04 2020-03-04 Injection molding process capable of preventing injection overflow

Publications (2)

Publication Number Publication Date
CN111331800A true CN111331800A (en) 2020-06-26
CN111331800B CN111331800B (en) 2022-04-19

Family

ID=71175990

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202010142386.5A Active CN111331800B (en) 2020-03-04 2020-03-04 Injection molding process capable of preventing injection overflow

Country Status (1)

Country Link
CN (1) CN111331800B (en)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103724791A (en) * 2014-01-02 2014-04-16 苏州艾兴无纺布制品有限公司 Ultrahigh-performance plastic film as well as preparation method and composite material thereof
CN105713241A (en) * 2016-04-15 2016-06-29 上海福助工业有限公司 Biodegradable thermoplastic starch resin film and preparation method thereof
CN105778232A (en) * 2016-04-15 2016-07-20 上海福助工业有限公司 Scraping-resistant PE film packing material and preparing method thereof

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103724791A (en) * 2014-01-02 2014-04-16 苏州艾兴无纺布制品有限公司 Ultrahigh-performance plastic film as well as preparation method and composite material thereof
CN105713241A (en) * 2016-04-15 2016-06-29 上海福助工业有限公司 Biodegradable thermoplastic starch resin film and preparation method thereof
CN105778232A (en) * 2016-04-15 2016-07-20 上海福助工业有限公司 Scraping-resistant PE film packing material and preparing method thereof

Also Published As

Publication number Publication date
CN111331800B (en) 2022-04-19

Similar Documents

Publication Publication Date Title
US10647824B2 (en) Thermoplastic elastomer resin powder and method for producing thermoplastic elastomer resin powder
US8007907B2 (en) Glass-containing molding composition and process for production of the same
CN105733249A (en) Composite polyamide material for large-thickness-tolerance precision injection molded part and injection molding method
CN111331800B (en) Injection molding process capable of preventing injection overflow
CN102850655A (en) Low-density automobile back door plate module and preparation method thereof
CN113278226A (en) Antifogging polypropylene master batch and preparation method thereof
CN112852178A (en) Noctilucent plastic injection molding part
CN114800985B (en) Rotational molding crosslinked polyethylene hand mold, composition and preparation method thereof
CN111518329A (en) High-content antifogging master batch taking white carbon black as oil storage slow-release agent and production process thereof
CN106366399A (en) HDPE modified material for improving pearly luster color masterbatch forming line and application of material
CN104194156A (en) Scratch-resistant injection molding material
CN109705517A (en) A kind of preparation method of fretting map ABS material and great surface quality lightweight injected plastics material
CN111234521A (en) High-gloss mirror glass fiber reinforced PA66 composite material and preparation method thereof
CN205167502U (en) Granulation is with novel extruder mould mouth
CN110041647A (en) A kind of high molecule plastic hollow plate preparation method
CN112708208B (en) Polypropylene composite material and preparation method thereof
CN111331801B (en) Injection molding process capable of resisting physical stress and freezing cracking
CN109438838B (en) Production process for effectively reducing splash or silver streaks of high-powder-content polypropylene composite material
CN112048104B (en) Preparation method of casting medium-temperature model wax
CN106965407B (en) PE bottle surface is blow molded frosted method
CN112341713A (en) Processing technology of environment-friendly wear-resistant high polymer material
CN113072764A (en) High-dispersion high-fluidity low-heat-sealing-temperature polyolefin extinction material
CN116852651A (en) One-mold multi-piece injection molding method for air flow cover air guide device
CN117024879A (en) Polypropylene micro-foaming material with low mold temperature sensitivity and preparation method thereof
JP4550150B1 (en) Glass-containing injection molded products

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant