ＤＪＫ List of Products and Services

Our company possesses multiple small twin-screw extruders and ancillary equipment for testing and prototyping. We undertake various tests and prototypes, including the formulation of polymer alloys, polymer blends, additives, and fillers, as well as reaction extrusion, degassing, solvent removal, and the elimination of unreacted components. We also offer evaluations of extrusion kneading properties, optimization of kneading conditions, and the prototyping and evaluation of compounds. Please feel free to consult us if you have any requests. 【Features】 ■ One-stop service from extrusion kneading tests to sample production and physical property measurement ■ Support for compound processing considerations *For more details, please download the PDF or feel free to contact us.

• Other contract services

We measure the resin flow length when injection molding is performed under certain conditions. The mold is designed with a resin injection port at the center, and a spiral groove with a constant spacing based on an Archimedean spiral is used. A flow velocity meter is incorporated within the cavity to measure the flow velocity immediately after injection. Additionally, a flow velocity sensor installed in the mold allows us to determine the initial flow velocity entering the cavity, as well as the shear rate and shear viscosity at the time of passing through the sensor. **Features** - Capable of calculating shear rate and shear viscosity during cavity passage - Allows comparison of flow length and shear viscosity *For more details, please download the PDF or feel free to contact us.*

• Contract measurement

We measure thermal conductivity using methods such as the disk heat flow meter method, the hot wire (probe) method, and the alternating current steady-state method. The measurement targets include disk-shaped test pieces (solids), powders, solids, and molten resins. Please feel free to consult us if you have any requests. 【Measurement Methods】 ■ Disk Heat Flow Meter Method ASTM E1530 (compliant) - A measurement method also known as the steady-state comparative method, referred to as the guarded heat flow meter method in ASTM E1530 - Measurement target: Disk-shaped test pieces (solids) ■ Hot Wire (Probe) Method JIS R 2616 (compliant), ASTM D5930 (compliant) - Direct measurement of thermal conductivity from the heat generated by the hot wire (heater wire) and the temperature rise - Measurement targets: Powders, solids, molten resins ■ Alternating Current Steady-State Method ISO 22007-6 (reference) - Measurement of the thermal conductivity of insulation materials using temperature waves - Measurement targets: Foams, insulation materials *For more details, please download the PDF or feel free to contact us.

• Contract measurement

Supercritical fluid (SCF) is a fluid that possesses both gas and liquid properties above its critical temperature and pressure. It has low viscosity and high diffusivity, making it advantageous for mass transfer compared to liquid solvents, and it can achieve significant differences in solubility with only changes in pressure. The technology of supercritical foaming molding utilizing SCF was established in the 1980s by MIT in the United States, and it is currently licensed under the name "MuCell(R)" by Trexel Inc. Our company conducts evaluation tests for supercritical foaming injection molding. Please feel free to consult us if you have any requests. [Test] ■ Molding tests using the client's product mold (on-site observation available) ■ Molding tests using molds owned by DJK (on-site observation available) - Foaming molding using a short shot method with a test piece mold - Full shot molding (shrinkage, warpage, dimensional accuracy, appearance of molded products) - Core-back molding (foaming ratio of approximately 1.5 to 2 times, up to a maximum of 6 times) *For more details, please download the PDF or feel free to contact us.

• Other contract services

Carbon Fiber Reinforced Polymer (CFRP) is a composite material made by combining lightweight polymers with lightweight, high-strength carbon fibers. The strength is enhanced through stress transfer between fibers mediated by the interface and matrix, allowing more fibers to effectively carry the load, contributing to strength development that exceeds the breaking strength of individual fibers (filaments). [Related Contract Services] ■ Evaluation and Modification of Matrix Resins - Epoxy Resins (impregnation, curing, properties of cured resins, processing considerations) - Thermoplastic Resins (flowability, impregnation, resin properties, resin modification) ■ Prototype and Improvement Studies of Prepregs and Composites - Impregnation and Lamination Conditions (vacuum press) - Interlaminar Adhesion, Toughness Improvement ■ Evaluation Testing of Composites - Mechanical Properties (tensile, compression, bending, shear, impact) - Composition (CF content, matrix resin analysis, residual fiber length) - Durability (thermal aging, heat cycles, fatigue properties) - Adhesion with Other Materials (adhesive bonding, insert molding) *For more details, please download the PDF or feel free to contact us.

• Composite Materials

The "Accelerated Weathering Test" is fundamentally based on outdoor exposure; however, since it takes a long time to assess performance, various accelerated tests have been implemented. Our company provides comprehensive support for product development for customers conducting accelerated weathering tests. Please feel free to consult us if you have any requests. 【Representative Testing Equipment】 ■ Sunshine Weather Meter (SWOM) - Capable of dew cycles as a high acceleration method ■ Xenon Weather Meter (XWOM) - Low degradation acceleration but high reproducibility ■ Metering Weather Meter - Utilizes strong ultraviolet light, resulting in exceptionally high acceleration ■ Ultraviolet Fluorescent Lamp Weather Meter - Conducts cycle tests combining irradiation and dark (condensation) *For more details, please download the PDF or feel free to contact us.

• Weather resistance test

The measurement can be applied to a wide range of materials such as plastics, resins, inks, paints, food, cosmetics, and pharmaceuticals, making it an important analytical method for understanding molecular structures and material properties. It is possible to measure the glass transition temperature of resins, viscosity and elasticity during melting, thermosetting behavior, steady-state viscosity, solid torsional vibrations, tension, compression, and more. 【Measurement Contents】 ■ Frequency dependence, temperature dependence, and time dependence measurements ■ Stress and strain dependence measurements ■ Thermosetting behavior ■ Steady-state viscosity and shear rate dependence measurements ■ Creep and recovery measurements *For more details, please download the PDF or feel free to contact us.

• others

"Reactive Processing" is a technology that finely controls the dispersed structure of non-phase-separated polymer alloys through a melting kneading process accompanied by chemical reactions. The method utilizing a fully intermeshing co-rotating twin-screw extruder is mainstream, offering various advantages such as efficient stirring, mixing, and degassing capabilities for high-viscosity fluids, as well as the ability to combine with subsequent processes (pelletizing, sheet processing). Please feel free to consult us if you have any requests. [Advantages] ■ Provision of a continuous reaction environment in a solvent-free, molten state ■ Individual supply control for diverse materials ■ High productivity *For more details, please download the PDF or feel free to contact us.

• Composite Materials

Polymer alloys are a technology that mixes multiple existing polymers with different characteristics to leverage their strengths while improving their weaknesses. This approach addresses the diversification and sophistication of performance requirements that are difficult to meet with a single polymer. Please feel free to consult us if you have any requests. 【Related Contract Research and Testing Services】 ■ Polymer Alloy Preparation - Compatibility studies of immiscible polymer systems - Reactive extrusion - Prototype production of partially miscible and immiscible polymer alloys using twin-screw extruders ■ Physical Property Evaluation and Composition Analysis - Mechanical properties - Thermal properties - Molding processability, etc. ■ Improvement and Compounding of Existing Alloys - Consideration of improvements to currently used existing polymer alloys based on your requests - Functional compounds incorporating fillers into polymer alloys *For more details, please download the PDF or feel free to contact us.

• Other polymer materials

"UV-curable resin" is a type of resin that forms a crosslinked structure through the reaction between oligomers and monomers with polymerization capabilities, such as vinyl groups, acrylate groups, and epoxy groups, initiated by radicals or cations generated by the irradiation of light (ultraviolet rays). Due to differences in the reaction mechanism (initiating species), it is classified into radical polymerization type and cationic polymerization type. In terms of resin variation and cost, radical polymerization type acrylate monomers and oligomers are the mainstream. 【Features】 ■ Cures at room temperature in a short time with minimal damage to the substrate ■ Energy-efficient ■ Solvent-free, resulting in lower environmental impact *For more details, please download the PDF or feel free to contact us.

• plastic

The test specimen (150±1×50±1×t mm) is held horizontally, and a 38mm flame is applied for 60 seconds to determine the burning rate and burning behavior over a distance of 100mm between the reference lines. UL94HF and HBF tests are conducted on foamed materials with a density of less than 250kg/m3.

• Contract measurement

Mount the test piece (125±5×13±0.5×t mm) vertically in the clamp and perform 5 seconds of direct flame exposure from a 125mm flame 5 times, then evaluate based on the combustion behavior. Hold the flat test piece (150±5×150±5×t mm) horizontally and perform 5 seconds of direct flame exposure from a 125mm flame 5 times from below, then evaluate based on the combustion behavior. The 5V test is conducted on materials that conform to V-0 or V-1 ratings.

• Contract measurement

A film test specimen (200±5×50±1×t mm) is rolled into a cylindrical shape, mounted vertically in a clamp, subjected to a 3-second indirect flame from a 20mm flame twice, and the burning behavior is used to determine VTM-0, VTM-1, VTM-2, or Not.

• Contract measurement

The test specimen (125±5×13±0.5×t mm) is held horizontally, and a 20mm flame is applied for 30 seconds to determine the combustion rate over a distance of 75mm between the reference lines.

• Contract measurement

Mount the test specimen (125±5×13±0.5×t mm) vertically in the clamp, perform two 10-second indirect flame tests with a 20mm flame, and determine the ratings of V-0, V-1, V-2, or Not based on its combustion behavior.

• Contract measurement

Apply voltage between platinum electrodes and drip the electrolyte until tracking failure occurs. Evaluate at a voltage that does not cause failure with the specified number of drops. - IEC60112 CTI (Comparative Tracking Index: Determine the voltage that withstands 50 drops) PTI (Proof Tracking Index: Prove that it withstands 50 drops at the specified voltage)

• Contract measurement

An arc discharge is generated at a specified interval between two tungsten electrodes on the surface of the test specimen, and the time until the sample breaks and the arc discharge disappears is also measured. - ASTM D495, JIS K6911

• Contract measurement

It is possible to evaluate the electrostatic properties of polymer materials. Charge decay measurements can be conducted in accordance with standards such as MIL-B-81705, EIA541, and NFPA99. Samples of various shapes can be measured (however, the measurement sizes specified in the standards must be adhered to).

• Contract measurement

Charge Decay Measurement Device STATIC HONESTMETER Type S-5109 (manufactured by Shishido Electrostatic Co., Ltd.) - Static Honestmeter (Corona Charging Method JIS L1094) - Static Decay Meter (Conductive Charging Method MIL, EIA, NFPA)

• Contract measurement

Apply a commercial frequency voltage of 50Hz or 60Hz across the electrodes with the test specimen in between, and determine the breakdown voltage of the sample. Insulation breakdown strength (max 70kV) (IEC60243, ASTM D149, JIS C2110), measurement methods: short-time method, step method, dielectric strength (1 minute, long duration), measurement atmosphere: in oil (RT to 200℃), in air.

• Contract measurement

The dielectric constant and dielectric loss tangent at high frequencies will be determined using the perturbation method of a hollow cavity resonator. - Cylindrical cavity resonator method Frequencies: 1GHz, 2.5GHz, 5GHz (Temperature: only room temperature)

• Contract Analysis

The mutual induction bridge method determines the dielectric constant and dielectric loss tangent from the capacitance and conductance of the measurement object at equilibrium. - Mutual dielectric bridge method (IEC60250, ASTM D150) Frequency 60 to 1 MHz, (Temperature range -60 to 200°C)

• Contract measurement

Using the same principle as the four-terminal method (current-voltage method), four needle-like electrodes are placed in a straight line on the sample. A constant current is passed between the outer two probes, and the potential difference that arises between the inner two probes is measured to determine the resistance. Next, the calculated resistance is multiplied by the sample thickness and the correction factor RCF (Resistivity Correction Factor) to calculate the volume resistivity. Compared to the four-terminal method, there is no need to form electrodes on the sample.

• Contract measurement

It is a standard for conductive rubber, but it is applied to resistance measurement of conductive plastics. Measurement method: Using electrodes arranged in parallel facing each other at both ends of the specimen, the volume resistivity is determined. A small current is passed through the outer electrode, and the voltage between the inner electrodes is measured to calculate the resistance.

• Contract measurement

While the volume resistivity and surface resistivity reflect the shape factors of the specimen, the insulation resistance is directly indicated by the resistance value (Ω) between the tapered pins. Measurement method: Similar to the measurement of the volume resistivity and surface resistivity of insulators, a voltage of 500V is applied between the electrodes of the tapered pins, and the resistance is measured after 1 minute.

• Contract measurement

Double Ring Electrode Method (IEC60093, ASTM D257, JIS K6911, JIS K6271) Measurement of resistivity of insulators in the range of 10^8 to 10^16 Ω. The electrical resistance is measured using an insulation resistance meter between circular electrodes, and the volume resistivity and surface resistivity are calculated from the electrode geometry. Measurement method: Apply 500V between the electrodes and measure the resistance value after 1 minute.

• Contract measurement

The low-temperature impact test is conducted in methanol/dry ice, and the temperature at which there is a 50% probability of failure is expressed as the embrittlement temperature.

• Contract measurement

Electric Appliance Investigation Committee B Method (in oil) The BPT is defined as the depth of indentation of 0.209mm when a φ5mm steel ball is pressed against the sample with a load of 20N for 1 hour at the test temperature in oil. IEC60695-10-2 and Electric Appliance Investigation Committee A Method measure using a "balancing" jig in an oven. DJK only conducts measurements using Method B.

• Contract measurement

In oil, the oil temperature is increased at a constant rate (often 50°C/h), and a needle with a cross-sectional area of 1 mm² is applied to the sample with a specified load, with the temperature at which the penetration depth reaches 1 mm being defined as the VSP.

• Contract measurement

JIS K7191, ISO 75, ASTM D648 The oil temperature is raised at a constant rate (120℃/h), and a specified bending stress is applied to the sample. The temperature at which the specified deflection is reached is referred to as the load deflection temperature. It is used as one of the indicators of the heat resistance of plastics.

• Contract measurement

This measurement method, also known as the steady-state comparison method, is referred to as the protective heat flow meter method in ASTM E1530. In this method, a reference sample with a known thermal conductivity is measured simultaneously, allowing for the accurate measurement of thermal conductivity without the need for absolute heat flow measurements. A heater and a reference calorimeter are in close contact to create a steady state with a temperature difference of approximately 30K between the top and bottom of the test specimen. The thermal conductivity is then determined from the temperature difference at both ends of the test specimen and the output of the reference calorimeter.

• Contract measurement

The standard TMA is temperature-dependent and has a unit of (1/°C), but the humidity-controlled TMA is designed for hygroscopic films and measures the extent of expansion or contraction due to humidity. The unit is 1/(%RH).

• Temperature and humidity measuring instruments

TMA (Thermomechanical Analysis) is a technique that measures the deformation of a material as a function of temperature by applying a non-oscillatory load while changing the temperature according to a controlled program. The following measurements can be performed with TMA: - Measurement of linear expansion coefficient and expansion rate - Measurement of glass transition temperature - Measurement of softening temperature Additionally, probes for tensile mode and penetration are available, allowing for the measurement of samples in film and sheet forms.

• Contract Analysis

When injecting polymer materials through injection molding, they are injected into a low-temperature mold under high temperature and high pressure, and then rapidly cooled to become solid. At this time, the polymer materials experience a decrease in volume due to cooling. PVT measurements assess the changes in behavior during cooling [P (pressure) - V (volume) - T (temperature)] and are used as simulation data for flow analysis and mold design. Additionally, the obtained specific volume (cm³/g) can be used to estimate the density changes at high temperatures.

• Contract measurement

Viscoelastic measurements using a rotational rheometer can be applied to a wide range of materials such as plastics, resins, inks, paints, food, cosmetics, and pharmaceuticals, making it an important analytical tool for understanding molecular structures and material properties.

• Contract measurement

- Tensile mode (JIS K7244-4 t ≤ 1mm) - Bending mode (JIS K7244-5 w10×L50×t2～3mm) Shear mode and compression mode are also possible. Dynamic viscoelasticity is measured by performing temperature sweep mode at constant frequency and frequency sweep at constant temperature to assess the rheology of solid materials.

• Contract Analysis

The friction coefficient test measures the friction coefficient when sliding on the same material or other materials. Please consult us regarding test pieces that do not conform to JIS K7125, such as test pieces with a thickness of 0.5 mm or more.

• Contract Analysis

This evaluates the abrasion and wear resistance of the sample surface. It allows for the observation of changes in characteristics such as thickness, mass, and optical diffusion after a specified number of rotations.

• Contract Analysis

It complies with both Method A (ring against disk, ring against ring) and Method B (pin against disk) of JIS K7218. Method A involves combinations of ring against disk or ring against ring, and is also known as the "Suzuki-Matsubara method" for sliding tests. Method B is a sliding test of pin against disk, which is also specified in ASTM D2716.

• Contract Analysis

Impact testing is a test that measures the resistance of a material when subjected to a high-speed load. There are several types of impact tests, including the pendulum-type Izod impact test, Charpy impact test, tensile impact test, and drop-weight impact tests such as the DuPont impact test and dart impact test. The Izod and Charpy impact tests typically involve notching the test specimen. By notching, stress is concentrated, which means the results are influenced by the notch shape and the method of notch fabrication.

• Impact Test

Impact testing is a test that measures the resistance of a material when subjected to a high-speed load. There are several types of impact tests, including the pendulum-type Izod impact test, Charpy impact test, tensile impact test, and drop weight impact tests such as the Du Pont impact test and dart impact test. The Izod and Charpy impact tests typically involve notching the test specimen. By introducing a notch, stress concentration occurs, which is influenced by the notch shape and the method of notch fabrication.

• Impact Test

Barcol hardness is a measurement method widely used in the quality control of GFRP. Barcol hardness is also a type of indentation hardness, and its mechanism is similar to that of durometer hardness. A conical indenter is pressed against the test specimen, and the maximum value is read.

• Composite Materials

Durometer hardness is a measurement method that is used more frequently for rubber and elastomers than for plastics. Durometer hardness is also a type of indentation hardness, but unlike Rockwell hardness, it is determined by the depth of the indentation under a test load. The scale is measured using type D (conical indenter) for plastics and type A (cylindrical) for rubber and elastomers, with a proper range of 20 to 90.

• Rubber

Rockwell hardness is a type of indentation hardness that incorporates creep behavior into hardness measurement, taking into account properties such as elastic modulus and recoverability. There are three scales: R, L, and M, with the R scale being the most commonly compared in catalogs, followed by the M scale. The standard specifies an appropriate range of 50 to 115, and it is noted that if the measurement exceeds 100, it is advisable to measure using the next harder scale. For values below HRR50, Rockwell hardness is deemed inappropriate, and it is preferable to choose durometer hardness instead.

• plastic

Attach strain gauges, either orthogonal or uniaxial, at 0° and 90° in the center of the test specimen to measure longitudinal and lateral strains. Since we will measure longitudinal strain with the strain gauge, we can also measure the modulus of elasticity simultaneously.

• Contract measurement