KR100356500B1 - A process for preparing polyolefin packing material having conductivity - Google Patents

Abstract

According to the invention, polyurethane 25-35% having a molecular weight of 500-3000, a hydroxyl value of 35-550, a viscosity of 770-30000; 50-60% polyolefins with a melt index of 150-500; 5-15% tackifier selected from terpene resins and C9 water-added petroleum resins; And 5-10% of xylene resin, an adhesive composition for imparting conductivity to a polyolefin foam packaging is provided.

The polyolefin-based packaging material according to the method of the present invention minimizes contaminants on the surface, improves conductivity, and improves problems such as unfoamed beads appearing on the surface when forming EPP and EPE beads. It is very useful as a lightweight packaging material for products.

Description

A process for preparing polyolefin packing material having conductivity}

The present invention is a semiconductor or by coating a carbon black and a conductive polymer on the surface of the resin using a predetermined adhesive in a pellet based on a polyolefin-based resin, more preferably a conductive bead having a foaming ratio of 15-35, The present invention relates to a process for producing a conductive expanded polypropylene or expandable polyethylene suitable as a packaging material for LCDs.

In the bead-type foam, to date, EPS products are most widely used as general-purpose packaging materials, but as the quality and precision of products are required, there is an increasing demand for higher quality and stability of product packaging. Against this background, olefin-based bead foams have been developed since the late 1970s as an alternative to reinforce the physical vulnerability of EPS products. Initially, research and development focused on crosslinked EPE foam having excellent physical properties, but it was difficult to industrialize due to problems such as complicated manufacturing process, difficulty of product recycling, and high production cost.

In order to solve the above problems of the EPS product, the development of a non-crosslinked foam that can be manufactured and recycled in a simple process has been progressed. As a result, non-crosslinked EPE (LLDPE) and EPP have been developed and marketed. Polypropylene resin, which is the raw material of EPP, has better impact resistance, repeatability, flexibility, and chemical resistance than EPS, and is lighter and better than PUF (polyurethane foam), and has higher rigidity of foam than EPE. It is advantageous to lighten the product. Using these properties, EPP is able to produce bumper cores, side impact blocks, seat inserts, arm rests, door liners and spoiler materials for automotive applications. liners), extension boxes, and monitors, LCDs, PCs, printers, CD-ROMs, medical devices, optical devices, semiconductors, packaging materials for audio and measuring devices, and various protective devices and helmets.

Moreover, in recent years, in the industrial and consumer electronics industry, electroconductive packaging that can attenuate static electricity to prevent rupture or deterioration of electronic components caused by dust pollution and electro-static discharge (ESD) caused by static electricity. There is an urgent need for the development of materials, especially in the field of monitors and LCDs, which are highly dependent on Japanese products and expensive.

As a coating method using polypropylene, a method of Japanese Patent Publication No. Hei 4-132742 is known, wherein polypropylene has been used as an automotive part because it has excellent rigidity, heat resistance, formability, and excellent vacuum forming and pressure forming. However, in this method, the adhesion of polypropylene was quite difficult, so the surface was used by corona treatment, high temperature oxidation treatment, and flame treatment. According to the patent, EVA VA: 28% and chlorinated polypropylene (CPE) CI: 28% Was used to prepare the adhesive.

According to the method disclosed in US Pat. No. 5,075,136 (Dec. 24, 1991), 15% ethylene, rubber, atactic-PP, graft carboxyl units were coated in IPP, Co-PP. A solvent was used for the coating and a composition of 80% by weight solvent and 20% polypropylene was used. However, even the method according to this patent could not satisfy the above-mentioned demands of the industrial field.

Accordingly, the present inventors have responded to the industrial needs as described above, and have a polyolefin-based (EPP, EPE) foamable packaging material suitable for packaging materials for semiconductors, LCDs, monitors, etc., having excellent conductivity, impact resistance, buffering property and chemical resistance. Research efforts have been made to develop.

Bead-type buffer materials should be selected in consideration of the economical efficiency of imparting proper buffering properties to the product to be packaged. In particular, recent trends have been made in the use of packaging materials that can reduce the weight of the packaging volume, reduce logistics costs and minimize the impact on the environment. I prefer.

Conventionally, a carbon black, carbon fiber, graphite, conductive filler is added to a resin such as polyolefin used in a packaging material, and a method of preparing a conductive compound using a half-barrier, kneader, single screw, or twin screw extruder has been used. The packaging material thus prepared is excellent in physical properties but somewhat unsuitable for light weight trend of the product, in order to solve this problem, the present invention provides a conductive EPP, EPE that can be reduced in weight by applying a conductive adhesive to the polyolefin resin. It provides a method for producing. In addition, the conductive polyolefin packaging material according to the present invention, in addition to improved conductivity, minimizes contaminants on the surface, has excellent characteristics in shrinkage after forming beads, and adhesive strength after molding.

In order to achieve the above object, the composition of the adhesive in the present invention is PU 25-35%, polyolefin 50-60%, tackifier 5-15% (terpene resin and C9 hydrogenated petroleum resin), xyl The ethylene resin is 5-10%, and as an additive, a wetting agent, an anti blocking agent, a silane coupling agent, a surfactant, and the like are used in an amount of 3-7%.

As the conductive material, carbon black and a conductive polymer, preferably conductive carbon black having a surface area of 900 m ² / g or more, and ionomers 700 and 800 doped with carbon with polyaniline and polypyrrole as the conductive polymer are used. Transparent forms use polypyrrole or polythiophene as the conductive polymer.

The production method of the conductive foam of the present invention is described in detail below.

First, as a polyol, polyester series [molecular weight: 500-3000 / hydroxyl value (KOH mg / g): 35-550, viscosity (cP / 25 ° C): 770-3000] and polyurethane (PU) using TDI as isocyanate Synthesize A certain amount of toluene, methyl ethyl ketone (MEK), dimethylformamide (DMF) and xylene are used to make terminally isocyanated prepolymers, and diamines or diols, which are low molecular weight chain extenders. Polyols and isocyanates are prepared between 3.1-4.5 moles each. Polyol, DMF and xylene were added to the flask and mixed at a temperature of 140 ± 20 ° C. for 30 minutes, and then reduced pressure was recovered to recover 30-60% of the solvent, and the temperature was 130 ± 20 ° C. to prepolymer. Synthesis is performed for 4-5 hours while dropping. After the temperature was lowered to 80-90 ° C., a diol, a chain extender catalyst of an amine system and a surfactant were added thereto, and the temperature was further raised to 150 ° C. or higher for 2-3 hours.

25 to 35% by weight of the polyurethane synthesized in this way, 50-60% of polyolefin resin of melt index (MI) 150 to 500, terpene resin, petroleum resin or acrylate (e.g. acrylic acid (AA), Methacrylic acid (MAA), methyl acrylate (MAM), ethyl acrylate (EAM), butyl acrylate (BAM), methyl methacrylate (MMA), 2-ethyl hexyl acrylate (2-EHAM) 5-15 While mixing the xylene resin, 0.1-0.3% of DAKIN-Unidine (see Structural Formula below) having a surface tension of 10 mN / m was added to lower the surface tension of the resin, followed by stirring at a constant speed. The adhesive is prepared by leaving it to dry for 12 to 20 hours at room temperature The solid content of the adhesive thus prepared is preferably 5-25%, viscosity 10-5000 cps.

[Unidine]

Vinyl chloride crosslinking monomer

<Durability>

Perfluoroalkyl acrylate alkyl acrylate

R ₁ = -CH ₃ , HR ₂ = -CH ₃ , H

<Water repellency, oil repellency, soil release> <film formation, flexibility>

In the coating method, a certain amount of pellets are introduced into the stirrer, and then the mixture is stirred at low temperature in the melting temperature (Tm) ± 30 ° C of each polymer, and then the carbon black, the conductive filler and the conductive polymer are stirred together with the coating solution for 1-2 hours. It is stirred at a speed of 20 to 100 rpm so as not to stick to each other by the adhesive. After coating, it is dried at room temperature, and heated to 100 ° C in water for 3-4 hours to evaluate the coating to check whether there are any foreign substances and residues, and check whether there is any change in the adhesive layer.

In order to make EPP and EPE products, 1000-2000 g of coating resin, 10-15 g of surfactant, 30-50 g of anti-fusion agent, 120-150 ml of isobutane and 40-100 g of water are added to the autoclave reactor and stirring is started. (Keep 100-500 rpm). Raise the thermal medium and internal temperature to ± 20 ° C and maintain this temperature until the end of the process. The pressure is maintained at 10-25 kg / cm ² . After 2-3 hours, the valve at the bottom of the reaction vessel and the foaming valve were connected to prepare the foaming, and the PP and PE pellets were changed to beads at 15-45 times the foaming ratio by pressure strengthening. A product having excellent conductivity change and adhesion by the chain between the beads and the vapor pressure in forming the final product is obtained. In particular, when the external force is applied, it is difficult to separate the foam beads, unlike the EPS, and the final tearing occurs. In addition, it is flexible and can be reused as a molded article preventing damage and non-crosslinked foam.

EXAMPLE

The present invention will be described in more detail by way of examples. However, the present invention is not limited to these examples.

Example 1

Synthesis of Polyurethane

Polyol [polyester series, molecular weight = 2000, hydroxyl value = 56.1] (100 g), DMF (15 g) and xylene (85 g) were added to the flask, mixed at a temperature of 140 ± 20 ° C. for 30 minutes, and then the solvent was dried under reduced pressure. 10% of the solution was recovered, and the temperature was 130 ± 20 ° C., 5g of a prepolymer and 95g of a polyol (90 g of toluene diisocyanate), 54 g of polyol, 54 g of H ₃ PO ₄ (phosphate 0.015 g) of JP504) was performed for 4-5 hours. After the temperature was lowered to 80-90 ° C, 0.5 g of a chain extender (Surfactant) (DC-193) 0.5 g of a chain extender (DEG (Diethylene glycol)) and 1 g of DBTL as a catalyst were added thereto, and the temperature was raised to 150 ° C or higher. It was synthesized for 2-3 hours.

Manufacture of adhesives

To 100 g of the polyurethane obtained above, 60 g of a polyolefin resin (EVA (Ml: 2500 VA: 14) 20, Melsen (adhesive polymer): MX25 20, CPP (chlorinated PP) 60), a tackifier (DCPD ( Dicyclopentadiene)) 10g. While putting xylene resin (XYLENE 10g), in order to lower the surface tension of the resin, 5g of DAKIN-unidine having a surface tension of 10 mN / m was added and stirred, followed by drying at room temperature for 15 hours to prepare an adhesive. .

Solid content of the obtained adhesive was 10%, and the viscosity was 100 cps.

Coating of adhesive

Polypropylene pellet (Tm: 135 ° C. Ml = 21-22) (100 g) was added to the reactor and stirred at low temperature at 110 ° C., followed by carbon black (0.5 g) and conductive polymer (polythiophene 2 g). It is stirred with the obtained adhesive coating liquid (0.3 g) for 1-2 hours, at a speed of 20 to 100 rpm so as not to stick to each other by the adhesive. After coating, it is dried at room temperature, and heated to 100 ° C in water for 3-4 hours to evaluate the coating to check whether there are any foreign substances and residues, and check whether there is any change in the adhesive layer.

Formation of foam beads

1500 g of the coating resin, 15 g of polyethylene glycol, 150 ml of isobutane, and 60 g of water were added to an autoclave reactor, and stirring was started (maintained at 100-500 rpm). The heat medium and internal temperature are raised to 130 ° C. and maintained at the end of the process. The pressure is maintained at 10-25 kg / cm ² . After 2-3 hours, the valve at the bottom of the reaction vessel and the foaming valve were connected to prepare the foaming, and the PP pellet was changed to bead at 30 times the foaming ratio by pressure strengthening.

Property test and comparison with conventional products

The surface state of the obtained EPP was evaluated by touching by hand whether the carbon black on the surface was smeared and whether the marking occurred on the paper. (Carbon black can be a source of contamination in LCD packaging.)

Adhesion was judged to be a phenomenon that breaks when the interface state between beads is pulled using a microscope or a tensile tester.

The surface state and adhesion of EPP obtained in this example were good, and the resistance value of the pellets was evaluated as E3, and the resistance value of the beads was E6.

Physical property test results of the EPP obtained above and the results of comparative tests with Japanese-made EPE foams conventionally used are shown in Table 1 below.

* Traditional Japanese foams have a lot of carbon black on their surface

According to this embodiment, the problem that the unfoamed beads are molded on the surface during EPP bead molding is improved.

Example 2

EPP was prepared in the same manner as in Example 1 except that the amount of the adhesive was changed to 0.5 part by weight and the amount of carbon black was 0.3 part by weight.

The surface condition and adhesion were good, and the resistance value of the pellet was E4, and the resistance value of the bead was E7.

Example 3

EPE was used in the same manner as in Example 1, except that 100 parts by weight of polyethylene (Tm: 115, LLDPE (Linear Low Polyethylene)) was used instead of polypropylene, and the amount of adhesive was changed to 0.6 part by weight and the amount of carbon black to 1 part by weight. Was prepared.

The surface condition and adhesion were good, and the resistance value of the pellet was E3, and the resistance value of the bead was E6.

Example 4

An EPE was prepared in the same manner as in Example 3, except that the amount of the adhesive was changed to 0.5 part by weight and the amount of carbon black was 0.8 part by weight.

The surface condition and adhesion were good, and the resistance value of the pellet was E4, and the resistance value of the bead was E7.

Example 5

EPE was prepared in the same manner as in Example 3, except that the amount of the adhesive was changed to 0.4 part by weight and the amount of carbon black was 0.6 part by weight.

The surface condition and adhesion were good, and the resistance value of pellets was evaluated as E6, and the resistance value of beads was E7.

As described above, the polyolefin-based packaging material according to the method of the present invention has minimized contaminants buried on the surface, improved conductivity, and improved problems such as unfoamed beads appearing on the surface when forming EPP and EPE beads. In particular, it can be usefully used as a lightweight packaging material for industrial and electronic products.

Claims (6)

25-35% of a polyurethane having a molecular weight of 500-3000, a hydroxyl value of 35-550, and a viscosity of 770-30000; 50-60% polyolefins with a melt index of 150-500; 5-15% tackifier selected from terpene resins and C9 hydrogenated petroleum resins; And adhesive composition for imparting conductivity to the polyolefin foam packaging material comprising 5-10% xylene resin. The method of claim 1, wherein the polyolefin composition (EVA Ml: 2500, VA: 14: 20-30%, Melsen (MX25): 20-30%, CPP: 40-60%) in order to increase the adhesion An adhesive composition for imparting conductivity to a polyolefin foam packaging material, further comprising. 2. The adhesive composition of claim 1 wherein the solid content is 5-25% and the viscosity is 10-5000 cps. delete delete delete