增塑剂:PVC的“软化剂”,邻苯类与非邻苯类之争,生物基增塑剂是新方向

塑料知识科普 发布时间: 2026-09-13 2329 阅读

A batch of PVC food-grade hoses was sent to supermarkets, and consumers complained about a "strange odor and oily residue on their hands." Upon inspection, the inner wall was found to have oily deposits. The supermarket demanded a complete recall, causing huge losses for the manufacturer. The formulator knew that they were still using the traditional DEHP phthalate plasticizer, which has high migration, and would no longer pass food contact compliance—essentially using an old formula to try to meet new regulations.

Turn back time a hundred years: PVC without plasticizers is as hard as a slab of stone; it is the plasticizers that turn it from a hard lump into a flexible hose.

This article is compiled by Ningbo Kolong New Materials Co., Ltd., which has long been engaged in the business of plastic raw materials and additives. The grade and batch information are subject to the actual supply channels.

Plasticizer Quick Reference Table: Phthalates, Non-Phthalates, Bio-based Three Categories

Plasticizers are added the most among all additives—calculated per hundred parts of resin, usually 20 to 60 parts are added. Which brand to choose depends on how soft a product you want to make, where you are selling it, and which country's regulations you need to comply with. The table below lists everything clearly on one page.

systemRepresentative varietiesKey parametersTypical productsAddition ratio (phr)
Phthalate general useDOP, DEHPCheap and versatile, some varieties are restrictedOrdinary soft PVC, artificial leather20-50
high molecular weight ortho-phenyleneDINP, DIDPMigration-resistant, durableElectric wires and cables, durable products30-60
Non-phthalateDOTP Di(2-ethylhexyl) terephthalateHeat-resistant, migration-resistant, compliantElectric wires and cables, automotive software30-60
Cold-tolerant specialDioctyl Adipate (DOA)Low temperature flexibilityFrost-resistant hoses, films10-30 (compound preparation)
Bio-basedEpoxidized soybean oil, citrate estersEnvironmentally friendly, food-gradeFood contact, toys10-40

Note: phr refers to parts per hundred parts of resin; the above is the general industry range, and specific grades and physical property parameters should be based on the official TDS of each manufacturer. First, determine the target hardness and compliance requirements, then select the system.

Figure 1  Plasticizers—Soft and flexible PVC hoses and films

Plasticizers are softeners for PVC, and the debate between ortho-phthalates and non-ortho-phthalates is timely.

This protagonist is the magician who makes rigid PVC soft. Ningbo Cologne New Materials Co., Ltd. has long been engaged in various plastic additives and modified materials, covering multiple domestic and international brand sources. It has stable supply channels for PVC additives such as plasticizers and heat stabilizers. The category of plasticizers is essentially the 'softener' of PVC—PVC is naturally hard and brittle, and it is entirely reliant on them to make the material soft and pliable.

Plasticizers are like applying lubricant between the PVC molecular chains; the chains can slide, and the plastic naturally becomes soft.

From a mechanistic point of view, plasticizer molecules insert themselves between PVC molecular chains, weakening the intermolecular forces and lowering the glass transition temperature, making the chain segments move more easily, so the material becomes softer and more flexible. It is the type of additive used in the largest amounts of all additives—in soft PVC, it is often added in twenty to thirty parts or even fifty to sixty parts, directly determining the softness and hardness of the final product.

The more frequently plasticizers are stuffed into PVC, the larger the gaps between the molecular chains become—this is how hard lumps are coaxed into becoming soft noodles.

The core issue in this category today is compliance: phthalates (like DOP, DEHP, etc.) are cheap and easy to use, but DEHP and others are regulated in toys, food contact, and medical fields; non-phthalate systems such as DOTP, DINCH, and citrate esters are more compliant; bio-based options like epoxidized soybean oil and citrate esters are environmentally friendly and renewable, representing a new direction.

Stuff the small molecules of flexible plasticizer between the rigid PVC chains, like leaving a gap between each carriage of a train.

Phthalates are cheap and easy to use, but DEHP has been banned in toys and food contact — don't use old formulas to bypass new compliance.

Quick check by type: DOP sales volume, DOTP compliance, epoxidized soybean oil is environmentally friendly

Although there are many varieties, grasping a few main lines can cover most soft PVC applications.

Which type of soft product to make, who to sell it to, and which country's regulations to follow—if you haven't figured out these three things clearly, choosing a plasticizer is just gambling on luck.

DOP (Dioctyl Phthalate/DEHP): The traditional mainstay of phthalates, cheap and well-balanced in overall performance, widely used in ordinary flexible PVC and artificial leather. Signals for choosing it: for general industrial soft products, not in contact with food or toys, cost-sensitive. Note: DEHP is restricted in multiple markets and applications, and should no longer be used for export and contact products.

Supply Notice: Non-phthalate plasticizers such as DOTP and epoxidized soybean oil can be supplied stably by Cologne New Materials, with migration and flash point data provided for each batch. Kilogram-scale samples are available for preliminary compatibility testing.

DINP, DIDP: High molecular weight phthalates, resistant to migration, durable, commonly used in wires, cables, and long-life products. Note: Although milder than DEHP, some markets still have limits on the total phthalate content, and regulations should be checked for exports.

DOTP (Dioctyl Terephthalate): A non-ortho phthalate main product, heat-resistant, migration-resistant, high volume resistivity, a compliant alternative for wires, cables, and automotive software. Signals for choosing it: replacing DOP, meeting environmental compliance, making heat-resistant and durable parts.

Epoxidized Soybean Oil (ESO): Acts as an auxiliary plasticizer and auxiliary heat stabilizer. It is bio-based, environmentally friendly, and cheaper than citrate esters, making it a common supporting ingredient in PVC soft products. Signals for choosing it: making food contact soft products, needing heat stabilization synergy, and wanting to reduce costs within compliance. Precautions: Its plasticizing efficiency is low when used alone and it cannot serve as the main plasticizer to achieve softness; it is usually used in combination with primary plasticizers like DOTP, DOP, etc., at 3-10 phr. The epoxy value should be kept stable; too high may precipitate, too low will not provide heat stabilization synergy.

Citrate esters: high-end bio-based plasticizers, compliant and friendly for food contact and toy-grade applications, used in teething toys, children's soft rubber, and medical grade soft PVC. Signals for choosing it: exported to EU toys, maternal and infant contact items, highlighting eco-friendly labels. Note: the price is significantly higher than ESO, generally not necessary for standard industrial soft products.

Hoses, wire insulation, artificial leather, disposable gloves — the soft PVC you've touched all have plasticizers at work behind the scenes.

The trouble with plasticizers: they are the additives used in the largest amounts, and they are also the ones most likely to be disliked because they can migrate.

Alternative Comparison: How to replace restricted substances like DEHP? First, look at this table

Regulations are tightening, and many old formulas containing DOP/DEHP need alternatives. Below are common directions and prerequisites for switching.

Original directionTypical applicationsBenchmark solutionSwitch premise
DOP/DEHPOrdinary soft PVCDOTP/DINPCompare hardness, migration resistance, low temperature, cost
DEHP (restricted use)Toys/Medical PartsDINCH/Citrate EsterToy/medical compliance, migration testing
Imported DOTPElectric wires and cablesDomestic DOTPComparison of heat resistance, volume resistivity, and migration resistance
Imported epoxy soybean oilEnvironmentally friendly and food-gradeDomestic ESOComparison of epoxy value, precipitation, and food compliance

The directions listed in the table are for reference only; the actual migration and hardness feel still need to be tested with samples.

When replacing plasticizers, migration and exudation comparisons need to be made. When Cologne New Materials sends kilogram-level DOTP/epoxidized soybean oil samples, reference data for flash point and migration are provided. Customers can first conduct compatibility and food contact compliance verification before switching.

For compliant soft products, go with DOTP or epoxidized soybean oil, and stop worrying about the small price difference of DEHP.

Quick Reference for Industry Scenarios: Wire materials and toy materials require two different formulas

Even though both are soft PVC, the choice of plasticizer is completely different for making electrical wires and cables versus making teething toys. Below, it is broken down by industry.

IndustryTypical productsThe parameters the customer asked about firstRecommendation systemCertification requirements
Electric wires and cablessoft foreskinHeat resistance, volume resistivityDOTP/DINPRoHS, cable standards
Toys and Maternal & Infant ProductsSoft rubber toys, teething toysCompliance, MigrationCitrate/DINCHEN71, GB 6675
Building materialsSealing strip, linoleumDurability, weather resistanceDINP/DOTPGB/T, REACH
PackagingFood hoses, filmsFood contactEpoxidized Soybean Oil/Citrate EsterGB 4806, FDA
Daily necessitiesGloves, synthetic leatherCost, feelDOP/DINP General PurposeRoHS

Here's a scenario: When producing soft rubber toys for export, DEHP and five other phthalates must not be detected. At this point, simply give up on phthalates and choose citrate esters or DINCH, pass the EN71 migration test first, and then discuss the feel.

If the plasticizer exudes and seeps oil, first check whether the added amount exceeds the limit and whether the compatibility is sufficient; don't just blame the formulation.

Dosage and pairing key points: the softness and hardness entirely depend on the proportion

The amount of plasticizer added directly determines the softness or hardness of the product and is the most prominent variable in the formula. The following four points are general guidelines.

Plasticization: When the chains loosen, the material becomes soft.

◆ General-purpose soft PVC: DOTP or DOP 30-50 phr, the amount is determined according to the target Shore hardness.

◆ Electric wires and cables: DOTP/DINP 40-60 phr, heat-resistant and migration-resistant, formulated with calcium-zinc heat stabilizer.

◆ Cold-resistant products: DOA dioctyl adipate mixed at 10-30 phr to improve low-temperature flexibility and toughness.

◆ Food/Toys: Epoxidized soybean oil or citric acid esters, compliance preferred, pay attention to synergy with stabilizers.

Key points for formulation: Plasticizers should be used together with PVC heat stabilizers (such as calcium-zinc), otherwise PVC is prone to decomposition and discoloration during processing; excessive addition can cause oil exudation and surface stickiness; bio-based plasticizers can be partially blended with phthalates to balance environmental protection and cost.

There is a basic principle for blending primary and auxiliary plasticizers: the primary plasticizer (such as DOTP, DOP, DINP) is responsible for bringing the hardness to the target value, accounting for more than 70% of the total plasticizer amount; the auxiliary plasticizer (such as epoxidized soybean oil, chlorinated paraffin, adipate esters) is responsible for making up shortcomings—ESO improves thermal stability, DOA improves low-temperature flexibility, and chlorinated paraffin reduces cost. The blending ratio is not decided arbitrarily: an imbalance between primary and auxiliary plasticizers will be unsatisfactory, too much auxiliary plasticizer means the primary plasticizer cannot maintain softness, while too much primary plasticizer raises cost and migration. The industry practice is to first determine the amount of primary plasticizer based on hardness, then add 3-10 phr of auxiliary plasticizer to target specific properties, and finally conduct re-testing for exudation and low-temperature flexibility to lock the formula.

There are two most common pitfalls in compounding: first, adding too many additives, which dilutes the main plasticizer, making the product appear soft but sticky or exuding when stretched, and becoming brittle in winter; second, choosing the wrong combination of main agent and additives, such as using DEHP-type main agents with ESO for food contact parts—ESO may be compliant, but the main agent already fails compliance, making it pointless. The correct sequence is to first determine the compliant list of main agents based on the intended use (for food or toys, directly exclude DEHP), then select the cost-effective options from the compliant main agents, and finally use additives to fill the gaps. Do not reverse the order by leaving the main agent on the restricted list just to add a little environmentally-friendly story with ESO.

What kind of soft product to make, who to sell it to, and which country's regulations to follow—once you think through these three things, whether it contains phthalates or not naturally has an answer.

Processing and compliance red lines: migration, precipitation, and regulations are hard lines

When there are problems with plasticizers, it's mostly due to migration and regulations. The table below lists the key links.

link; segment; partReference valueThe consequences of doing wrong
Addition amountAccording to the target hardness of 20-60 phrExcess → oozing oil, sticky surface
CompatibilityEvaluation of Compatibility Between Plasticizers and PVCIncompatible → Migration, Spraying, Sticky
Regulatory useRestricted substances such as DEHP are prohibited based on their useNon-compliant → Toys/Food are returned
With heat stabilizerPlasticizers and simultaneous use of calcium and zinc for heat stabilizationNot suitable → processing and decomposition, discoloration

Compliance red line: Phthalate plasticizers are restricted by REACH Annex XVII and other regulations. For toys, food contact, and medical uses, choose non-phthalate or bio-based options; for exporting to the EU, check REACH, and for food-grade applications, comply with GB 4806/FDA. Migration testing and compliance declarations should be archived with the shipment.

FAQ: The Five Most Common Questions Asked by Purchasing and Formulation Engineers

Q1: Can domestic plasticizers replace imported materials?

Sure, for bulk varieties like DOTP, epoxy soybean oil, and DOP, the gap between domestic and imported products is already very small, and domestically produced brands with stable batches are completely sufficient. However, for high-end medical grade applications, exports to the EU where strict phthalate restrictions apply, and scenarios requiring extremely low leaching, imported products still have advantages in purity and batch consistency. To replace them, kilogram-level samples should first be tested for hardness, migration resistance, low-temperature performance, and compliance items. After passing, small-batch verification can be done before scaling up. For comparison samples, kilogram-level samples can be requested, along with migration and flash point data for side-by-side comparison.

Q2: Why does the surface of soft PVC become oily and sticky?

It is mostly due to excessive addition of plasticizers or insufficient compatibility with PVC, causing small molecules to gradually migrate to the surface. The solution is to reduce the amount to the range required for the target hardness, switch to a variety with better compatibility, or blend with high molecular weight plasticizers to reduce migration.

Q3: What is the difference between DOTP and DOP?

DOP is phthalene, which is cheap and comprehensive, but has limitations; DOTP is non-phthalene, heat-resistant, migration-resistant, and has higher volumetric resistivity, making it more suitable for wires, cables, and compliant products. DOTP feels slightly harder, so the number of parts should be adjusted appropriately when formulating.

Q4: What makes bio-based plasticizers expensive?

Bio-based plasticizers such as epoxy soybean oil and citrate esters are environmentally friendly, renewable, and food-friendly. Their price and supply are affected by agricultural product trends, with some varieties higher than traditional phthals. Its value lies in compliance and environmental labeling, so cost-sensitive general industrial soft products do not need to be forced.

Q5: Does the more plasticizer you add, the softer it gets?

Generally, the more parts, the softer and lower the strength, but once the compatibility limit is exceeded, oil will precipitate, making the surface stickier and reducing performance. The goal is not to get softer as many as possible, but to find the appropriate quantity based on the target Shore hardness.

Three-step selection checklist: choose the softer to comply

◆ Step 1 · Determine hardness and use: first determine the target Shore hardness, cold resistance, and whether it comes into contact with food/toys/medical products. This determines the quantity and compliance threshold.

◆ Step 2 · Select system: general industrial use DOTP/DINP; food toys use citrate/DINCH; cold-resistant compound adinate; environmentally friendly focus on bio-based products.

◆ Step 3 · Nuclear Regulations and Migration: Check REACH phthalm limits and food contact standards, conduct precipitation migration tests, prepare heat stabilizers, first trial hardness before mass production.

Compliant with soft additives is more important than soft but cheaper .

Plasticizer selection must simultaneously consider softness, migration, low temperature resistance, and compliance requirements. Orthophthalmic compounds (DEHP/DBP) have been restricted in the toy and food contact sectors; DOTP, DINCH, citrate, and epoxy soybean oil are mainstream alternatives. Cologne New Materials can provide migration, flash point, low-temperature brittle temperature reference data and food contact compliance documents for different plasticizers; kilogram-scale samples support precipitation and softness comparisons first.

Last year, a factory producing PVC hoses was removed from supermarkets — consumers complained about odors and oil leakage. Kelong New Materials recommended DOTP as a substitute for DEHP, combined with a small amount of epoxy soybean oil to improve stability, and sent kilogram-level samples. After trial production, the customer's odor was significantly reduced, migration precipitation levels dropped below compliance lines, food contact testing was passed again, and the supermarket resumed shelves. The factory manager said they originally thought switching plasticizers would greatly increase costs, but calculated it only cost about 200 yuan per ton, but this avoided the loss of removal from shelves.

Is your plasticizer phthalite or non-phthalic?

Statement: The brands, trademarks, and product names mentioned in this article belong to their respective original manufacturers. This article is a third-party material selection knowledge sharing. The grades, parameters, prices, certifications, and application cases mentioned are for reference only. Please refer to the latest official information and batch inspection reports from each manufacturer. This article does not constitute any procurement or investment advice. Readers are responsible for any actions based on it

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