You might need to find Chinese source. I'll translate some of them. (There are a lot of ancient Chinese wasn't translated in modern time.)
Earliest in (501 A.D) 6th century Southern Qi Dynasty : 《南史·齊紀下·東昏侯》
"(帝)乃聚兵為固守計，...。尚書舊事，悉充紙鎧。" - "In order to defend (the incoming enemy), (The emperor) ordered to gather his army, ... Ancient books and old documents, are all been used to make armors." The last (effective) emperor called his army to defend his falling dynasty (the dynasty fallen the next year), using probably the national library and offices documents to make armors. Although he failed (not because he lost the battle, but one of the royal family relatives stage a coup), and it's the first creative idea of using paper armors.
In Tang Dynasty (9th century) : 《新唐書》卷113
"置備征軍，凡千人，襞紙為鎧，勁矢不能洞。" - "Preparing equipments and recruiting an army, totally thousands of soldiers. Cutting papers to make armors, even the strongest bow(arrows) can not shoot through them". This early documentation is probably why so many translations said it's good against arrows. (It doesn't say it's bad against other weapons). But if an army all used this as primary armors, it must be effective in some way.
A little later after Tang Dynasty (10th century) : 《南唐書》卷三
"民間又有自相率、以紙為甲、農器為兵者，號白甲兵。" - "Civilians managing their own militia armies, using paper to make armors, and farming equipments as weapons. Calling themselves White Armor Army". As the great Tang Dynasty fallen, there is chaos and farmers rose up on their own, and even forming their own short lived kingdoms in southern China, called "South Tang".
The next united Dynasty - Northern Song in 11th century :
"诏江南、淮南州军造纸甲三万", "詔委逐路州軍以遠年賬籍製造" - "The emperor ordered the two southern states : (their names 江南, 淮南) armies to make and equip 30 thousand paper armors", "The emperor entrusted the following state armies to make armors using old accounting books and documents." These records showed that at this era not only it was been produced at large quantity, but also made the recycling of papers quite effectively.
When the Song Dynasty lost northern China, the Southern Song Dynasty at 12th - 13th century :
"所有本寨軍器都稍足備，但水軍所需者紙甲。今本寨乃有鐵甲百副，今當存留其半，而以五十副就本軍換易紙甲。" - "This army camp has most of the military equipments ready, but the naval army (not navy, but soldiers fight on terrains with plenty of rivers and lakes in southern China) needs paper armors. Now this camp already has 100 steel armors, so (the captain of the camp) I will remain half of them, and trade the rest half 50 sets with (equal amount) of paper armors." This record shows surprisingly not only it's at the same equality as steel armors, but also it's been used at wet terrains. It's better after it's wet, not as you think that it will be less effective.
As late until 17th century (1621) in Ming Dynasty :
"天雨地濕，鐵甲易生金肅爛，必不可用矣。倭夷土賊率用火銃神器，而甲有藤有角，皆可用。但鉛子俱能洞入，且體重難久。今擇其利者，步兵性有輯甲，用輯布不等。若紙綿俱薄，則箭亦可入，無論鉛子。今需厚一寸用綿密輯，可長至膝。" - "(In southern China) Steel armors are easily rusted, and must not used them. Foreign invaders (Japanese and others) and pirates use fire arms, there are many materials like rattan whip to be used to make armors against them. But lead bullets can still penetrate them, and they are to heavy for soldiers to wear for a long time. Now the better way is to make composition armors for the foot solders, using papers and cloth as materials. If the paper and cotton cloth are too thin, even the arrows can shoot through them, let along lead bullets. You need at least 1 Chinese inch (3.4 cm in Ming Dynasty) thick and pact tightly with composition materials (to be affective), and making them as body length from neck to knee." As for more than a thousand years of making paper armor, it reaches at peak that it became a standard armor type, and possible had standard making processes and materials. And possibly only lost due to the increase effectiveness of fire arms render it obsolete (as any other armors). It can even withstand the early less effective fire arms.
Hence most of it doesn't mentioned it's effectiveness against other weapons, but it does equip a large portion of an army in latter era. It's safe to say that it has to be some what effective to be able to withstand other armies using steel armors.
Author
Topic: Why are blunt weapons ever better than edged? (Read 12139 times)