CN112810116A

CN112810116A - Plastic uptake processing method and product

Info

Publication number: CN112810116A
Application number: CN202011591499.XA
Authority: CN
Inventors: 金亚东; 姚志贤; 周玉波; 朱正平
Original assignee: Ningbo Solartron Technology Co Ltd
Current assignee: Ningbo Solartron Technology Co Ltd
Priority date: 2020-12-29
Filing date: 2020-12-29
Publication date: 2021-05-18
Anticipated expiration: 2040-12-29
Also published as: CN112810116B

Abstract

The invention relates to a plastic uptake processing method and a product thereof. The plastic uptake processing method comprises the following steps: providing a resin material; preheating the resin material; and carrying out plastic suction molding on the preheated resin material, wherein in the plastic suction molding process, a heating system is adopted to heat a plastic suction mold so as to heat the resin material; the first temperature of the plastic suction molding process is 20-30 ℃ lower than the softening point of the resin material.

Description

Plastic uptake processing method and product

Technical Field

The invention relates to the field of plastic uptake processing, in particular to a plastic uptake processing method and a product thereof.

Background

The backlight module is one of the key components of a Liquid Crystal Display (Liquid Crystal Display Panel), and because Liquid Crystal does not emit light, the backlight module has the function of supplying sufficient light sources with uniform brightness and distribution, so that the backlight module can normally Display images.

The reflective plate is an important component of the backlight mold. In the traditional technology, the reflecting plate is produced by using a plastic suction processing method, and when the thickness of the reflecting plate is within the range of 0.1mm-0.35mm, the reflecting plate after heat setting is easy to shrink, so that the reflecting plate is easy to bulge and wrinkle.

Therefore, a new plastic uptake processing method is needed, which can prepare products with the thickness of 0.1mm-0.35mm, and the products have smooth surfaces and good mechanical properties.

Disclosure of Invention

In view of the above, it is necessary to provide a blister processing method and a product thereof.

A plastic uptake processing method comprises the following steps:

providing a resin material;

preheating the resin material; and

carrying out plastic suction molding on the preheated resin material,

wherein, in the plastic suction molding process, a heating system is adopted to heat the plastic suction mold so as to heat the resin material;

the first temperature of the plastic suction molding process is 20-30 ℃ lower than the softening point of the resin material.

In one embodiment, the resin material has a tensile strength of 50MPa or more at 90 ℃ to 130 ℃ and an elongation at break of 40% or more.

In one embodiment, the resin material includes a reflective film having an ABA type three-layer structure, the a layer being a support layer and the B layer being a reflective layer.

In one embodiment, the reflective film has a thickness of 0.1mm to 0.55 mm.

In one embodiment, the second temperature is 90 ℃ to 130 ℃ during the preheating.

In one embodiment, the first temperature is 50 ℃ to 130 ℃ during the blister forming process.

In one embodiment, in the plastic suction forming process, the negative pressure value is 5kg-15kg, and the processing time is 6s-20 s.

In one embodiment, after the step of blister forming, a cooling step is further included. In the cooling step, the cooling speed is 20-40 ℃/min.

In the blister molding process of the present invention, the resin material is heated to a temperature within the range of 20 ℃ to 30 ℃ below its softening point. In this temperature range, the molecular chain of the resin material can be stretched and moved by an external force, and the resin material has good formability; meanwhile, the molecular chain of the resin material generates orientation under the action of external force, so that the mechanical property of the product can be improved. The resin material is heated by adopting a heating mould, so that the resin material can be uniformly heated, and a product with a flat surface is obtained.

An article prepared by the above method is applied to the field of reflecting plates.

The product provided by the invention has the advantages of thin thickness, good formability and smooth surface, and can improve the utilization rate of a light source, improve the display effect of a liquid crystal panel and improve the economic benefit when the reflecting plate is prepared.

Drawings

FIG. 1 is a flow chart illustrating a method for manufacturing a reflective plate according to the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below by way of embodiments with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In the present invention, md (machine direction) refers to the machine direction, i.e., the feed direction; td (transverse direction) refers to the transverse direction, i.e., perpendicular to the direction of feed.

In the present invention, the reflective film is a film-like resin material and can be stored in a rolled state. The reflecting plate is a finished product formed by plastic suction, has certain structural/mechanical rigidity, and can be kept for a long time without deformation at normal temperature.

The invention provides a plastic uptake processing method, which comprises the following steps:

s1, providing a resin material;

s2, preheating the resin material; and

and S3, carrying out plastic suction molding on the preheated resin material.

In the plastic suction molding process, a heating system is adopted to heat the plastic suction mold so as to heat the resin material; the first temperature of the plastic suction molding process is 20-30 ℃ lower than the softening point of the resin material.

In one embodiment, the resin material has a tensile strength of 50MPa or more at 90 ℃ to 130 ℃ and an elongation at break of 40% or more. It is preferable that the reflective film has a heat shrinkage rate in a Machine Direction (MD) of 0.5% or less and a heat shrinkage rate in a Transverse Direction (TD) of 0.2% or less at a temperature of 90 to 105 c, in consideration of the deformation rate of the film within a controllable range. The temperature condition means that the mechanical property of the material can meet the requirement at any test temperature in a corresponding temperature range.

In one embodiment, the resin material includes a reflective film having an ABA type three-layer structure, the a layer is a support layer, and the B layer is a reflective layer.

Wherein, the material of the A layer comprises a first polyester resin, a first inorganic particle and a toughening resin. The first polyester resin includes at least one of Polyethylene Terephthalate (PET) and polybutylene Terephthalate. The first inorganic particles include at least one of calcium carbonate, silica, titanium dioxide, barium sulfate. The toughening resin imparts toughness to the reflective film, and may have good tensile strength and elongation at break. The toughening resin is one of Maleic Anhydride (MAH) grafted polyethylene, Maleic Anhydride (MAH) grafted Styrene-Ethylene-butylene-Styrene block copolymer (SEBS), Glycidyl Methacrylate (GMA) grafted polyolefin Elastomer (POE). The MAH-grafted polyethylene may be MAH-grafted High Density Polyethylene (HDPE) or MAH-grafted linear Low Density Polyethylene (LDPE). In order to ensure the toughening effect, the mass fraction of the toughening resin is not less than 0.1%; however, when the addition amount is too high, the toughening agent effect is saturated, the improvement of the toughening effect by further increasing the addition amount is not obvious, the reflectivity of the reflective film is reduced by the excessively high toughening agent, and the mass fraction of the toughening resin is not more than 2%. The first polyester resin accounts for 97-98.9% of the layer A by mass; the first inorganic particles account for 1% by mass; the mass fraction of the toughening resin is 0.1-2%. Preferably, the mass fraction of the first polyester resin in the support layer is 97.5% -98.5%; the mass fraction of the first inorganic particles is 1%; the mass fraction of the toughening resin is 0.5-1.5%.

The material of the B layer includes a second polyester resin, second inorganic particles, and an incompatible resin. The second polyester resin comprises at least one of polyethylene terephthalate and polybutylene terephthalate. The incompatible resin means a resin incompatible with the second polyester resin, including polyolefin-based resins. Since the incompatible resin is incompatible with the second polyester resin, voids can be created around the incompatible resin during stretching, thereby forming cells in the reflective layer. At this time, the incompatible resin may be considered to be located substantially at the center of the cells. In order to facilitate the formation of the cells, the incompatible resin is preferably at least one of polypropylene, polymethylpentene, and cyclic olefin copolymer having a small critical surface tension. The particle size of the incompatible resin is not limited, but is preferably 0.2 μm to 0.3. mu.m. The presence of the cells can increase the reflectivity of the reflective film. The pore size of the cells is not limited, and is preferably 0.3 μm to 5 μm. The second inorganic particles include at least one of titanium dioxide, barium sulfate, calcium carbonate, and alumina. Preferably, the second inorganic particles are titanium dioxide, because titanium dioxide has good physical and chemical stability, a high refractive index, good shielding properties, and can provide a higher reflectance.

In one embodiment, the reflective film may be an intumescent reflective film. The thickness of the reflecting film is 0.1mm-0.55mm, preferably 0.1mm-0.35 mm.

In the present invention, when the second temperature in the preheating process is too low, the resin material is insufficiently preheated, the formability of the product is poor, and the second temperature is too high, which may decompose the resin material and cause energy waste. In one embodiment, the second temperature is 90 ℃ to 130 ℃, preferably 110 ℃ to 130 ℃.

In one embodiment, the heating system of the plastic suction molding process comprises at least one heating assembly, and the temperature of each heating assembly is independently controlled by a PLC (programmable logic controller) electric control system. In one embodiment, the heating unit of the heating system is a ceramic infrared heating tile, and the heating unit is matched with a PLC (programmable logic controller) electric control system, so that the temperature of each ceramic infrared heating tile can be accurately and respectively adjusted, and the heating temperature of each part of the mold can be adjusted according to requirements, so that the reflecting plate with a smooth surface can be obtained.

In the invention, in the plastic suction forming process, the first temperature is too low, the molecular chain of the polymer is not easy to move, the product is not easy to form, and the product forming property is poor; if the first temperature is too high, the polymer macromolecules are not easy to generate orientation in the forming process, even if the orientation is generated, the formed orientation structure is loosened due to the thermal motion of molecules, the orientation is removed, the performance of the polymer cannot be maintained, and the mechanical property of the product is poor. In one embodiment, the first temperature is from 50 ℃ to 130 ℃, preferably from 70 ℃ to 90 ℃.

In one embodiment, the negative pressure value in the plastic suction molding process is 5kg-12 kg. In order to obtain a product with flat surface and good formability, the negative pressure value in the plastic suction forming process is preferably 7kg-10 kg.

In the invention, the plastic suction molding time is too short, which is not beneficial to product molding; if the forming time is too long, energy waste will be caused, and the production cost will also be increased. In one embodiment, the duration of the blister forming process is 10s-35s, preferably 12s-25 s.

In one embodiment, the blister forming process further comprises a cooling step. In the present invention, the cooling step may be selected from natural cooling, air cooling, water cooling, etc., preferably air cooling.

In one embodiment, the cooling rate is 20 ℃/min to 40 ℃/min. The cooling rate is preferably 30-40 deg.C/min to obtain a smooth-surfaced article.

The invention also provides a product prepared by the plastic uptake processing method, and the product is a reflecting plate. The reflector plate provided by the invention has good mechanical properties.

In one embodiment, the reflector plate is in the shape of a shallow dish having trapezoidal sidewalls and a rectangular bottom. The depth of the tray is 5mm-35mm, and the length of the upper edge of the corresponding tray is 250mm-1700 mm; the width is 150mm-1100 mm; the bottom area of the tray accounts for more than 50% of the sum of the bottom area and the side wall area. The thickness of the reflecting plate is 0.1mm-0.55mm, preferably 0.15mm-0.35 mm.

Example 1

A resin material is provided, the resin material has an ABA three-layer structure, wherein the layer A is a support layer and the layer B is a reflecting layer. The layer A comprises 98.9 mass percent of PET resin, 1 mass percent of silicon dioxide particles and 0.1 mass percent of toughening resin based on the total mass of the layer A. The reflecting layer comprises 60 mass percent of PET resin (intrinsic viscosity is 0.68dL/g), 20 mass percent of polymethylpentene and 20 mass percent of titanium dioxide based on the total mass of the B layer. Preheating the resin material to 90 ℃, keeping the temperature for 10s, and carrying out plastic suction molding on a plastic suction machine. The conditions of plastic suction molding are as follows: the temperature of the plastic suction molding is 50 ℃, the negative pressure value of the plastic suction molding is 8kg, and the time of the plastic suction molding is 10s, so that the prefabricated product is obtained. The preform was then cooled for 8 seconds by air cooling to obtain a reflector plate.

The reflector plate is in the shape of a shallow plate with trapezoidal side walls and a rectangular bottom. The depth of the tray is 23mm, the length of the upper edge of the tray is 957mm, and the width of the tray is 540 mm. The thickness of the reflecting plate is 0.188mm, wherein the thickness of the two A layers accounts for 18% of the total thickness, and the thickness of the B layer accounts for 82% of the total thickness.

Example 2-example 45

The preparation method is basically the same as that of the example 1, and the specific reaction conditions are shown in the table 1.

TABLE 1 specific reaction conditions for the examples

The tensile strength, elongation at break, heat shrinkage at 85 c and thickness of the reflection plates prepared in examples 1 to 45 were measured, and the specific test results are shown in table 2.

TABLE 2 Properties of the reflecting plate

As is clear from tables 1 and 2, the light-reflecting plate having good moldability can be obtained by the vacuum forming method of the present invention. Wherein the longitudinal tensile strength of the prepared reflecting plate is greater than 81MPa, and the transverse tensile strength is greater than 71 MPa; the longitudinal elongation breaking rate is more than 78 percent, and the transverse tensile breaking rate is more than 50 percent; at 85 ℃, the heat shrinkage rates in the transverse direction and the longitudinal direction are both less than 0.1 percent, and the high-temperature-resistant composite material has good mechanical property and high temperature resistance.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A plastic uptake processing method is characterized by comprising the following steps:

providing a resin material;

preheating the resin material; and

carrying out plastic suction molding on the preheated resin material,

2. The blister processing method according to claim 1, wherein the resin material has a tensile strength of 50MPa or more and an elongation at break of 40% or more at 90 ℃ to 130 ℃.

3. The blister processing method according to claim 1, wherein the resin material includes a reflective film having an ABA type three-layer structure, the a layer being a support layer and the B layer being a reflective layer.

4. The blister processing method of claim 3, wherein the reflective film has a thickness of 0.1mm to 0.55 mm.

5. The blister processing method of claim 1, wherein the second temperature is 90 ℃ to 130 ℃ during the pre-heating.

6. The blister processing method according to claim 1, wherein the first temperature is 50 ℃ to 130 ℃ during the blister forming.

7. The blister processing method according to claim 1, wherein the processing time is 6s to 20s for a negative pressure value of 5kg to 12kg during the blister forming process.

8. The blister processing method according to claim 1, further comprising a cooling step after the blister forming step.

9. The blister processing method according to claim 1, wherein in the cooling step, the cooling rate is 20 ℃/min to 40 ℃/min.

10. An article produced by the process of any one of claims 1-9, wherein the article is used in the field of reflective panels.