PURGING COMPOUND FOR RESIN PROCESSING MACHINE

Abstract

A purging compound for removing a processing residue comprising a resin (C) to be purged, from a resin processing machine, comprising: a thermoplastic resin (A) and a non-ionic additive (B) of the following Formula (I) having a melting or softening point of lower than 150° C.:

Rn—X   (I)

(where R is a hydrophobic organic group, n is an integer of 1 or more, and X is a polar group), wherein a MFR (280° C. and a load of 2.16 kg) is 30 g/10 min or less, the difference of the solubility parameter between the resin (A) and the resin (C) is +1.6 to −1.6 (cal/cm.sup.3).sup.1/2, the difference of the solubility parameter between the additive (B) and the resin (C) is +1.6 to −1.6 (cal/cm.sup.3).sup.1/2, and the difference of the solubility parameter between the additive (B) and the hydrophobic organic group R is 0.7 (cal/cm.sup.3).sup.1/2 or more.

Claims

1. A purging compound for removing a processing residue comprising a resin (C) to be purged, from a resin processing machine, the purging compound comprising: a thermoplastic resin (A) and a non-ionic additive (B) represented by the following Formula (I) having a melting point or a softening point of lower than 150° C.:
Rn—X   (I) (in Formula (I), R is a hydrophobic organic group, n is an integer of 1 or more, and X is a polar group), wherein a melt flow rate (MFR) under conditions of 280° C. and a load of 2.16 kg is 30 g/10 min or less, a difference (SP1−SP2) between a solubility parameter (SP1) of the thermoplastic resin (A) and a solubility parameter (SP2) of the resin (C) to be purged is from +1.6 to −1.6 (cal/cm.sup.3).sup.1/2, a difference (SP3−SP2) between a solubility parameter (SP3) of the non-ionic additive (B) and the SP2 is from +1.6 to −1.6 (cal/cm.sup.3).sup.1/2, and a difference (SP3−SP4) between the SP3 and a solubility parameter (SP4) of the hydrophobic organic group R is 0.7 (cal/cm.sup.3).sup.1/2 or more.

2. The purging compound for a resin processing machine according to claim 1, wherein the thermoplastic resin (A) comprises at least one selected from the group consisting of a styrene-based resin and a polyester-based resin.

3. The purging compound for a resin processing machine according to claim 1, wherein the thermoplastic resin (A) comprises a styrene-based resin or a polyester-based resin, and a content of the styrene-based resin or the polyester-based resin in the purging compound for a resin processing machine is 40% by mass or more.

4. The purging compound for a resin processing machine according to claim 1, wherein the non-ionic additive (B) comprises a lubricant or a surfactant, and a content of the lubricant or the surfactant in the purging compound for a resin processing machine is 10% by mass or less.

5. The purging compound for a resin processing machine according to claim 1, wherein the SP1 and the SP3 are from 9 to 11 (cal/cm.sup.3).sup.1/2.

6. The purging compound for a resin processing machine according to claim 1, wherein the resin (C) to be purged is a styrene-based resin and/or a polyester-based resin.

7. A method of cleaning an inside of a resin processing machine, the method comprising using the purging compound for a resin processing machine according to claim 1.

8. Use of the purging compound for a resin processing machine according to claim 1 in cleaning of a resin processing machine.

9. The purging compound for a resin processing machine according to claim 2, wherein the thermoplastic resin (A) comprises a styrene-based resin or a polyester-based resin, and a content of the styrene-based resin or the polyester-based resin in the purging compound for a resin processing machine is 40% by mass or more.

10. The purging compound for a resin processing machine according to claim 2, wherein the non-ionic additive (B) comprises a lubricant or a surfactant, and a content of the lubricant or the surfactant in the purging compound for a resin processing machine is 10% by mass or less.

11. The purging compound for a resin processing machine according to claim 2, wherein the SP1 and the SP3 are from 9 to 11 (cal/cm.sup.3).sup.1/2.

12. The purging compound for a resin processing machine according to claim 2, wherein the resin (C) to be purged is a styrene-based resin and/or a polyester-based resin.

13. A method of cleaning an inside of a resin processing machine, the method comprising using the purging compound for a resin processing machine according to claim 2.

14. Use of the purging compound for a resin processing machine according to claim 2 in cleaning of a resin processing machine.

Description

EXAMPLES

[0100] Hereinafter, the present disclosure will be described in more detail with reference to Examples and Comparative Examples. The present disclosure is not limited to the following examples unless the gist thereof is exceeded.

[0101] Components used in Examples and Comparative Examples are as follows.

[0102] <Thermoplastic Resin (A) [0103] (A-1) PET (polyethylene terephthalate) [0104] (A-2) AS (styrene-acrylonitrile copolymer) (ratio of styrene: acrylonitrile was 70:30) [0105] (A-3) PC (Polycarbonate) [0106] (A-4) ABS (styrene-butadiene-acrylonitrile copolymer) (ratio of styrene:butadiene:acrylonitrile was 45:30:25) [0107] (A-5) and (A-6) PS (polystyrene) [0108] (A-7) LDPE (low density polyethylene)

[0109] The solubility parameters SP1 of (A-1) to (A-7) determined by the Fedors' estimation method and the melt flow rates (MFR) (g/10 min) measured under conditions of 280° C. and a load of 2.16 kg (in accordance with ISO 1133) are summarized in Table 1.

TABLE-US-00001 TABLE 1 MFR SP1 Thermoplastic resin (A) [g/10 min] [(cal/cm.sup.3).sup.1/2] A-1 PET 23 10.8 A-2 AS 16 9.9 A-3 PC 6 9.9 A-4 ABS 18 9.8 A-5 PS 12 9.3 A-6 PS 40 9.3 A-7 LDPE 6 7.7

[0110] <Non-Ionic Additive (B)> [0111] (B-1) Glyceryl stearate [0112] (B-2) Stearic acid amide [0113] (B-3) Ethylene bis stearic acid amide [0114] (B-4) Stearyl alcohol [0115] (B-5) Stearic acid [0116] (B-6) Isostearyl alcohol <Other Non-Ionic Additives> [0117] (B-7) Polyethylene glycol (number average molecular weight: 10,000) [0118] (B-8) Sodium dodecyl sulfate

[0119] The melting points or the softening points of (B-1) to (B-8), and the solubility parameter SP3 of (B-1) to (B-8) determined by the Fedors' estimation method and the solubility parameter SP4 of hydrophobic organic group R of (B-1) to (B-8) are summarized in Table 2.

TABLE-US-00002 TABLE 2 Additive (B) Melting point and other or softening SP3 SP4 SP3 − SP4 additives point [° C.] [(cal/cm.sup.3).sup.1/2] [(cal/cm.sup.3).sup.1/2] [(cal/cm.sup.3).sup.1/2] B-1 62 10.2 8.3 1.9 B-2 100 9.8 8.3 1.5 B-3 145 9.6 8.3 1.3 B-4 50 9.5 8.3 1.2 B-5 69 9.1 8.3 0.8 B-6 Liquid at 8.8 7.7 1.1 normal temp B-7 55 9.6 9.6 0.0 B-8 206 Unknown Unknown Unknown

[0120] <Resin to be Purged (C)> [0121] (C-1) PA66 (polyamide 66) [0122] (C-2) PET (polyethylene terephthalate) [0123] (C-3) PBT (Polybutylene terephthalate) [0124] (C-4) ABS (styrene-butadiene-acrylonitrile copolymer) (ratio of styrene:butadiene:acrylonitrile was 45:30:25) [0125] (C-5) PC (Polycarbonate) [0126] (C-6) PE (polyethylene)

[0127] The solubility parameters SP2 of (C-1) to (C-6) determined by the

[0128] Fedors' estimation method are summarized in Table 3.

TABLE-US-00003 TABLE 3 SP2 Resin (C) to be purged [(cal/cm.sup.3).sup.1/2] C-1 PA66 11.1 C-2 PET 10.8 C-3 PBT 10.6 C-4 ABS 9.8 C-5 PC 9.9 C-6 PE 7.7

[0129] The methods for measurement and evaluation of the purging compounds obtained in Examples and Comparative Examples are as follows.

[0130] [Performance Evaluations]

(Extrudability)

[0131] During preparation of each resin composition in Examples and Comparative Examples, the shape of strands and pelletization from an extruder were observed and evaluated according to the following evaluation criteria. [Evaluation Criteria]p O (good): Strands were formed stably and the sizes of pellets were hence uniform.

[0132] x (poor): Strands were not formed stably and the sizes of pellets were thus not uniform.

[0133] Unstable formation of strands is generally undesirable because it is considered to be caused by degradation or uneven distribution of the additive (B), leading to variations in quality, uneven performance, etc.

[0134] (MFR)

[0135] The melt flow rate (MFR) (g/10 min) of pellets of each purging compound obtained in Examples and Comparative Examples was measured under the conditions of 280° C. and a load of 2.16 kg in accordance with ISO 1133.

[0136] (Cleanability)

[0137] The cleanability of each purging compound obtained in Examples and Comparative Examples was evaluated using an injection molding machine provided with a multi-cavity hot runner for 96 preforms. The mold clamping was set to 350 t and the cycle time of a single shot was set to 20 seconds.

[0138] The resin (C) to be purged used as the staining material was dyed blue by mixing 5% by mass of a master batch colored with phthalocyanine blue with respect to 100% of the resin (C) to be purged in order to identify switching to purging.

[0139] A sufficient amount of the colored resin (C) to be purged was made to flow inside the cylinder so that it adhered sufficiently to the inner wall of the injection molding machine, and complete replacement of the discharged resin by the blue resin was confirmed. Next, a molding operation was conducted in the similar manner, and it was confirmed that the hot runner and the cavity were also filled with the colored resin (C) to be purged.

[0140] Thereafter, each purging compound obtained in Examples and Comparative Examples was then fed into the cylinder so that the inside of the cylinder was cleaned first. To check the cleaning performance inside the cylinder, the nozzle tip on the cylinder side was moved away from the mold and only the colored resin (C) to be purged (stain) inside the cylinder was discharged, which was visually confirmed.

[0141] Next, after the cylinder cleaning was completed, the nozzle was touched to the mold and the purging compound was made to flow into the hot runner under the same conditions as normal molding conditions, so that cleaning was performed while molding was being carried out.

[0142] Because the amount of the purging compound varies depending on the type of the resin (C) to be purged, the evaluation was made through comparison of the amount of the purging compound with the amount of the product (natural product) required when a non-colored target resin (C) was made to flow.

[Evaluation Criteria]

[0143] ⊚ (excellent): The colored resin (C) to be purged was completely discharged, and was purged with an amount of 1/3 or less of the amount when the natural product was made to flow.

[0144] O (good): The colored resin (C) to be purged was completely discharged, and was purged with an amount of more than 1/3 to 1/2 or less of the amount when the natural product was made to flow.

[0145] Δ (acceptable): The colored resin (C) to be purged was completely discharged and was purged with an amount of more than 1/2 to 1/1 or less of the amount when the natural product was made to flow.

[0146] x (poor): The colored resin (C) to be purged was not completely discharged and remained even when purged with an amount of more than 1/1 of the amount when the natural product was made to flow.

[0147] (Non-Remaining Ability)

[0148] The non-remaining ability of the purging compound per se inside a cylinder and a hot runner was evaluated using an injection molding machine provided with a multi-cavity hot runner for 96 preforms. After purging work was conducted until the purging compound was discharged, an uncolored resin (C) to be purged (natural product) was made to flow inside the cylinder and the hot runner of the molding machine in this order, in the similar manner to the evaluation for cleanability described above, and replacement of the purging compound was visually evaluated. [Evaluation Criteria]

[0149] ⊚ (excellent): No purging compound remained, and when the resin (C) to be purged (natural product) was made to flow, replacement with the natural product occurred within 10 molding shots.

[0150] O (good): Almost no purging compound remained, and when the resin (C) to be purged (natural product) was made to flow, replacement with the natural product occurred within 11 or more and 20 or less molding shots.

[0151] Δ (acceptable): The purging compound remained, but when the resin (C) to be purged (natural product) was made to flow, replacement with the natural product occurred within 21 or more and 40 or less molding shots.

[0152] x (poor): The purging compound remained, and replacement was difficult or 41 or more molding shots were required when the resin (C) (natural product) to be purged was made to flow.

Examples 1 to 12 and Comparative Examples 1 to 6

[0153] A resin composition containing the respective components at the ratios (% by mass) as listed in Table 4 was preliminarily mixed for 5 minutes using a tumbler blender, and the obtained mixture was melted and kneaded as such using a twin screw extruder (TEM58SS manufactured by Shibaura Machine Co., Ltd.). The extrusion conditions at this time were as follows: a cylinder setting temperature of 280° C. (200° C. only in Comparative Example 5 where A-7 resin was used alone) and a feed rate of 10 kg/hour. The melt kneaded product thus obtained was extruded into strand form, cooled with water, and then cut by a strand cutter to obtain a purging compound in pellet form.

Comparative Example 7

[0154] A purging compound was produced by mixing and dispersing B-2 and B-3 into A-2 for 5 minutes using a tumbler blender in the formulation ratios listed in Table 4.

[0155] Measurement and evaluation results of the obtained purging compound compositions are summarized in Table 4.

TABLE-US-00004 TABLE 4 Thermoplastic resin (A) Non-ionic additive (B) and other non-ionic additivies A-1 A-2 A-3 A-4 A-5 A-6 A-7 SP1 B-1 B-2 B-3 B-4 B-5 B-6 B-7 B-8 SP3 [% by mass] [(cal/ ] [% by mass] [(cal/ ] Example 1 97 10.8 3 10.2 Example 2 97 9.9 1 2 9.7 Example 3 97 9.9 9.1 Example 4 95 9.8 5 9.5 Example 5 95 9.3 8.8 Example 6 0 9.8 3 9.6 Example 7 20 78 9.7 2 9.8 Example 8 47 10.0 1 1 1 Example 9 70 9.2 2 1 9.3 Example 10 20 9.3 3 2 9.0 Example 11 20 73 9.6 4 1 9.6 Example 12 5 9.9 4 1 9.6 Comp. Ex. 1 8 10.8 1 10.2 Comp. Ex. 2 9.3 8.8 Comp. Ex. 3 95 9.9 9.6 Comp. Ex. 4 7.7 9.1 Comp. Ex. 5 9.9 1 2 9.7 Comp. Ex. 6 92 10.8 8 Unknown Comp. Ex. 7 9.9 1 2 9.7 Resin (C) to be Resin type SP2 SP1 − SP2 SP3 − SP2 Non- [—] [(cal/ ] [(cal/ ] [(cal/ ] [—] [ ] [—] [—] Example 1 C-1 11.1 −0. −0.9 28 Example 2 C-2 10. −0.9 −1.1 20 Example 3 C-3 10.6 −0. −1.3 12 Example 4 C-4 9.8 0.0 −0.3 22 Example 5 C-4 9.8 −0.5 −1.0 1 Example 6 C-2 10.8 −1.0 −1. 25 Example 7 C-2 10.8 − .1 −1.0 15 Example 8 C-3 10.6 −0.6 −0.7 19 Example 9 C-3 9.9 −0.6 18 Example 10 C-4 9.8 −0.3 −0.8 22 Example 11 C- 10.8 −1. −3.2 23 Example 12 C-1 11.1 − .2 −1.5 26 Δ Comp. Ex. 1 C-2 10.8 −0.6 X 6 X Comp. Ex. 2 C- 9.8 −0. −1. X 1 Δ Comp. Ex. 3 C- 10.6 −0.7 −1.0 16 Δ Δ Comp. Ex. 4 C- 10.8 −3.1 −1.7 X 14 X Δ Comp. Ex. 5 C-6 2. 2.0 20 Δ Comp. Ex. 6 C- 10.8 0. Unknown Δ Δ Comp. Ex. 7 C-2 10.8 −0.9 −1.1 — Δ indicates data missing or illegible when filed

[0156] From the evaluation results, it was seen that purging compounds containing a thermoplastic resin (A) and a non-ionic additive (B) having solubility parameters close to that of a resin (C) to be purged had better cleanability and non-remaining characteristic. Further, by controlling the solubility parameters of the thermoplastic resin (A) and the non-ionic additive (B), the non-ionic additive (B) was made to be uniformly dispersed during extrusion, which prevented reduction in the cleaning performance caused by extreme bleed-out and reduced viscosity.

INDUSTRIAL APPLICABILITY

[0157] According to the present disclosure, design of the combination of a resin and additives constituting a purging compound for a resin processing machine can be easily made based on solubility parameters, and the inside of a very complicated hot runner can be favorably cleaned. A purging compound can be prepared in a manner that it is tailored to the type of the resin to be